/[gxemul]/trunk/src/net/net_ip.c
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Revision 32 - (hide annotations)
Mon Oct 8 16:20:58 2007 UTC (16 years, 7 months ago) by dpavlin
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++ trunk/HISTORY	(local)
$Id: HISTORY,v 1.1421 2006/11/06 05:32:37 debug Exp $
20060816	Adding a framework for emulated/virtual timers (src/timer.c),
		using only setitimer().
		Rewriting the mc146818 to use the new timer framework.
20060817	Adding a call to gettimeofday() every now and then (once every
		second, at the moment) to resynch the timer if it drifts.
		Beginning to convert the ISA timer interrupt mechanism (8253
		and 8259) to use the new timer framework.
		Removing the -I command line option.
20060819	Adding the -I command line option again, with new semantics.
		Working on Footbridge timer interrupts; NetBSD/NetWinder and
		NetBSD/CATS now run at correct speed, but unfortunately with
		HUGE delays during bootup.
20060821	Some minor m68k updates. Adding the first instruction: nop. :)
		Minor Alpha emulation updates.
20060822	Adding a FreeBSD development specific YAMON environment
		variable ("khz") (as suggested by Bruce M. Simpson).
		Moving YAMON environment variable initialization from
		machine_evbmips.c into promemul/yamon.c, and adding some more
		variables.
		Continuing on the LCA PCI bus controller (for Alpha machines).
20060823	Continuing on the timer stuff: experimenting with MIPS count/
		compare interrupts connected to the timer framework.
20060825	Adding bogus SCSI commands 0x51 (SCSICDROM_READ_DISCINFO) and
		0x52 (SCSICDROM_READ_TRACKINFO) to the SCSI emulation layer,
		to allow NetBSD/pmax 4.0_BETA to be installed from CDROM.
		Minor updates to the LCA PCI controller.
20060827	Implementing a CHIP8 cpu mode, and a corresponding CHIP8
		machine, for fun. Disassembly support for all instructions,
		and most of the common instructions have been implemented: mvi,
		mov_imm, add_imm, jmp, rand, cls, sprite, skeq_imm, jsr,
		skne_imm, bcd, rts, ldr, str, mov, or, and, xor, add, sub,
		font, ssound, sdelay, gdelay, bogus skup/skpr, skeq, skne.
20060828	Beginning to convert the CHIP8 cpu in the CHIP8 machine to a
		(more correct) RCA 180x cpu. (Disassembly for all 1802
		instructions has been implemented, but no execution yet, and
		no 1805 extended instructions.)
20060829	Minor Alpha emulation updates.
20060830	Beginning to experiment a little with PCI IDE for SGI O2.
		Fixing the cursor key mappings for MobilePro 770 emulation.
		Fixing the LK201 warning caused by recent NetBSD/pmax.
		The MIPS R41xx standby, suspend, and hibernate instructions now
		behave like the RM52xx/MIPS32/MIPS64 wait instruction.
		Fixing dev_wdc so it calculates correct (64-bit) offsets before
		giving them to diskimage_access().
20060831	Continuing on Alpha emulation (OSF1 PALcode).
20060901	Minor Alpha updates; beginning on virtual memory pagetables.
		Removed the limit for max nr of devices (in preparation for
		allowing devices' base addresses to be changed during runtime).
		Adding a hack for MIPS [d]mfc0 select 0 (except the count
		register), so that the coproc register is simply copied.
		The MIPS suspend instruction now exits the emulator, instead
		of being treated as a wait instruction (this causes NetBSD/
		hpcmips to get correct 'halt' behavior).
		The VR41xx RTC now returns correct time.
		Connecting the VR41xx timer to the timer framework (fixed at
		128 Hz, for now).
		Continuing on SPARC emulation, adding more instructions:
		restore, ba_xcc, ble. The rectangle drawing demo works :)
		Removing the last traces of the old ENABLE_CACHE_EMULATION
		MIPS stuff (not usable with dyntrans anyway).
20060902	Splitting up src/net.c into several smaller files in its own
		subdirectory (src/net/).
20060903	Cleanup of the files in src/net/, to make them less ugly.
20060904	Continuing on the 'settings' subsystem.
		Minor progress on the SPARC emulation mode.
20060905	Cleanup of various things, and connecting the settings
		infrastructure to various subsystems (emul, machine, cpu, etc).
		Changing the lk201 mouse update routine to not rely on any
		emulated hardware framebuffer cursor coordinates, but instead
		always do (semi-usable) relative movements.
20060906	Continuing on the lk201 mouse stuff. Mouse behaviour with
		multiple framebuffers (which was working in Ultrix) is now
		semi-broken (but it still works, in a way).
		Moving the documentation about networking into its own file
		(networking.html), and refreshing it a bit. Adding an example
		of how to use ethernet frame direct-access (udp_snoop).
20060907	Continuing on the settings infrastructure.
20060908	Minor updates to SH emulation: for 32-bit emulation: delay
		slots and the 'jsr @Rn' instruction. I'm putting 64-bit SH5 on
		ice, for now.
20060909-10	Implementing some more 32-bit SH instructions. Removing the
		64-bit mode completely. Enough has now been implemented to run
		the rectangle drawing demo. :-)
20060912	Adding more SH instructions.
20060916	Continuing on SH emulation (some more instructions: div0u,
		div1, rotcl/rotcr, more mov instructions, dt, braf, sets, sett,
		tst_imm, dmuls.l, subc, ldc_rm_vbr, movt, clrt, clrs, clrmac).
		Continuing on the settings subsystem (beginning on reading/
		writing settings, removing bugs, and connecting more cpus to
		the framework).
20060919	More work on SH emulation; adding an ldc banked instruction,
		and attaching a 640x480 framebuffer to the Dreamcast machine
		mode (NetBSD/dreamcast prints the NetBSD copyright banner :-),
		and then panics).
20060920	Continuing on the settings subsystem.
20060921	Fixing the Footbridge timer stuff so that NetBSD/cats and
		NetBSD/netwinder boot up without the delays.
20060922	Temporarily hardcoding MIPS timer interrupt to 100 Hz. With
		'wait' support disabled, NetBSD/malta and Linux/malta run at
		correct speed.
20060923	Connecting dev_gt to the timer framework, so that NetBSD/cobalt
		runs at correct speed.
		Moving SH4-specific memory mapped registers into its own
		device (dev_sh4.c).
		Running with -N now prints "idling" instead of bogus nr of
		instrs/second (which isn't valid anyway) while idling.
20060924	Algor emulation should now run at correct speed.
		Adding disassembly support for some MIPS64 revision 2
		instructions: ext, dext, dextm, dextu.
20060926	The timer framework now works also when the MIPS wait
		instruction is used.
20060928	Re-implementing checks for coprocessor availability for MIPS
		cop0 instructions. (Thanks to Carl van Schaik for noticing the
		lack of cop0 availability checks.)
20060929	Implementing an instruction combination hack which treats
		NetBSD/pmax' idle loop as a wait-like instruction.
20060930	The ENTRYHI_R_MASK was missing in (at least) memory_mips_v2p.c,
		causing TLB lookups to sometimes succeed when they should have
		failed. (A big thank you to Juli Mallett for noticing the
		problem.)
		Adding disassembly support for more MIPS64 revision 2 opcodes
		(seb, seh, wsbh, jalr.hb, jr.hb, synci, ins, dins, dinsu,
		dinsm, dsbh, dshd, ror, dror, rorv, drorv, dror32). Also
		implementing seb, seh, dsbh, dshd, and wsbh.
		Implementing an instruction combination hack for Linux/pmax'
		idle loop, similar to the NetBSD/pmax case.
20061001	Changing the NetBSD/sgimips install instructions to extract
		files from an iso image, instead of downloading them via ftp.
20061002	More-than-31-bit userland addresses in memory_mips_v2p.c were
		not actually working; applying a fix from Carl van Schaik to
		enable them to work + making some other updates (adding kuseg
		support).
		Fixing hpcmips (vr41xx) timer initialization.
		Experimenting with O(n)->O(1) reduction in the MIPS TLB lookup
		loop. Seems to work both for R3000 and non-R3000.
20061003	Continuing a little on SH emulation (adding more control
		registers; mini-cleanup of memory_sh.c).
20061004	Beginning on a dev_rtc, a clock/timer device for the test
		machines; also adding a demo, and some documentation.
		Fixing a bug in SH "mov.w @(disp,pc),Rn" (the result wasn't
		sign-extended), and adding the addc and ldtlb instructions.
20061005	Contining on SH emulation: virtual to physical address
		translation, and a skeleton exception mechanism.
20061006	Adding more SH instructions (various loads and stores, rte,
		negc, muls.w, various privileged register-move instructions).
20061007	More SH instructions: various move instructions, trapa, div0s,
		float, fdiv, ftrc.
		Continuing on dev_rtc; removing the rtc demo.
20061008	Adding a dummy Dreamcast PROM module. (Homebrew Dreamcast
		programs using KOS libs need this.)
		Adding more SH instructions: "stc vbr,rn", rotl, rotr, fsca,
		fmul, fadd, various floating-point moves, etc. A 256-byte
		demo for Dreamcast runs :-)
20061012	Adding the SH "lds Rm,pr" and bsr instructions.
20061013	More SH instructions: "sts fpscr,rn", tas.b, and some more
		floating point instructions, cmp/str, and more moves.
		Adding a dummy dev_pvr (Dreamcast graphics controller).
20061014	Generalizing the expression evaluator (used in the built-in
		debugger) to support parentheses and +-*/%^&|.
20061015	Removing the experimental tlb index hint code in
		mips_memory_v2p.c, since it didn't really have any effect.
20061017	Minor SH updates; adding the "sts pr,Rn", fcmp/gt, fneg,
		frchg, and some other instructions. Fixing missing sign-
		extension in an 8-bit load instruction.
20061019	Adding a simple dev_dreamcast_rtc.
		Implementing memory-mapped access to the SH ITLB/UTLB arrays.
20061021	Continuing on various SH and Dreamcast things: sh4 timers,
		debug messages for dev_pvr, fixing some virtual address
		translation bugs, adding the bsrf instruction.
		The NetBSD/dreamcast GENERIC_MD kernel now reaches userland :)
		Adding a dummy dev_dreamcast_asic.c (not really useful yet).
		Implementing simple support for Store Queues.
		Beginning on the PVR Tile Accelerator.
20061022	Generalizing the PVR framebuffer to support off-screen drawing,
		multiple bit-depths, etc. (A small speed penalty, but most
		likely worth it.)
		Adding more SH instructions (mulu.w, fcmp/eq, fsub, fmac,
		fschg, and some more); correcting bugs in "fsca" and "float".
20061024	Adding the SH ftrv (matrix * vector) instruction. Marcus
		Comstedt's "tatest" example runs :) (wireframe only).
		Correcting disassembly for SH floating point instructions that
		use the xd* registers.
		Adding the SH fsts instruction.
		In memory_device_dyntrans_access(), only the currently used
		range is now invalidated, and not the entire device range.
20061025	Adding a dummy AVR32 cpu mode skeleton.
20061026	Various Dreamcast updates; beginning on a Maple bus controller.
20061027	Continuing on the Maple bus. A bogus Controller, Keyboard, and
		Mouse can now be detected by NetBSD and KOS homebrew programs.
		Cleaning up the SH4 Timer Management Unit, and beginning on
		SH4 interrupts.
		Implementing the Dreamcast SYSASIC.
20061028	Continuing on the SYSASIC.
		Adding the SH fsqrt instruction.
		memory_sh.c now actually scans the ITLB.
		Fixing a bug in dev_sh4.c, related to associative writes into
		the memory-mapped UTLB array. NetBSD/dreamcast now reaches
		userland stably, and prints the "Terminal type?" message :-]
		Implementing enough of the Dreamcast keyboard to make NetBSD
		accept it for input.
		Enabling SuperH for stable (non-development) builds.
		Adding NetBSD/dreamcast to the documentation, although it
		doesn't support root-on-nfs yet.
20061029	Changing usleep(1) calls in the debugger to to usleep(10000)
		(according to Brian Foley, this makes GXemul run better on
		MacOS X).
		Making the Maple "Controller" do something (enough to barely
		interact with dcircus.elf).
20061030-31	Some progress on the PVR. More test programs start running (but
		with strange output).
		Various other SH4-related updates.
20061102	Various Dreamcast and SH4 updates; more KOS demos run now.
20061104	Adding a skeleton dev_mb8696x.c (the Dreamcast's LAN adapter).
20061105	Continuing on the MB8696x; NetBSD/dreamcast detects it as mbe0.
		Testing for the release.

==============  RELEASE 0.4.3  ==============


1 dpavlin 32 /*
2     * Copyright (C) 2004-2006 Anders Gavare. All rights reserved.
3     *
4     * Redistribution and use in source and binary forms, with or without
5     * modification, are permitted provided that the following conditions are met:
6     *
7     * 1. Redistributions of source code must retain the above copyright
8     * notice, this list of conditions and the following disclaimer.
9     * 2. Redistributions in binary form must reproduce the above copyright
10     * notice, this list of conditions and the following disclaimer in the
11     * documentation and/or other materials provided with the distribution.
12     * 3. The name of the author may not be used to endorse or promote products
13     * derived from this software without specific prior written permission.
14     *
15     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18     * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25     * SUCH DAMAGE.
26     *
27     *
28     * $Id: net_ip.c,v 1.4 2006/09/05 06:13:28 debug Exp $
29     *
30     * Internet Protocol related networking stuff.
31     */
32    
33     #include <stdio.h>
34     #include <stdlib.h>
35     #include <string.h>
36     #include <unistd.h>
37     #include <sys/socket.h>
38     #include <sys/time.h>
39     #include <sys/types.h>
40     #include <errno.h>
41     #include <fcntl.h>
42    
43     #include "misc.h"
44     #include "net.h"
45    
46    
47     /* #define debug fatal */
48    
49    
50     /*
51     * net_ip_checksum():
52     *
53     * Fill in an IP header checksum. (This works for ICMP too.)
54     * chksumoffset should be 10 for IP headers, and len = 20.
55     * For ICMP packets, chksumoffset = 2 and len = length of the ICMP packet.
56     */
57     void net_ip_checksum(unsigned char *ip_header, int chksumoffset, int len)
58     {
59     int i;
60     uint32_t sum = 0;
61    
62     for (i=0; i<len; i+=2)
63     if (i != chksumoffset) {
64     uint16_t w = (ip_header[i] << 8) + ip_header[i+1];
65     sum += w;
66     while (sum > 65535) {
67     int to_add = sum >> 16;
68     sum = (sum & 0xffff) + to_add;
69     }
70     }
71    
72     sum ^= 0xffff;
73     ip_header[chksumoffset + 0] = sum >> 8;
74     ip_header[chksumoffset + 1] = sum & 0xff;
75     }
76    
77    
78     /*
79     * net_ip_tcp_checksum():
80     *
81     * Fill in a TCP header checksum. This differs slightly from the IP
82     * checksum. The checksum is calculated on a pseudo header, the actual
83     * TCP header, and the data. This is what the pseudo header looks like:
84     *
85     * uint32_t srcaddr;
86     * uint32_t dstaddr;
87     * uint16_t protocol; (= 6 for tcp)
88     * uint16_t tcp_len;
89     *
90     * tcp_len is length of header PLUS data. The psedo header is created
91     * internally here, and does not need to be supplied by the caller.
92     */
93     void net_ip_tcp_checksum(unsigned char *tcp_header, int chksumoffset,
94     int tcp_len, unsigned char *srcaddr, unsigned char *dstaddr,
95     int udpflag)
96     {
97     int i, pad = 0;
98     unsigned char pseudoh[12];
99     uint32_t sum = 0;
100    
101     memcpy(pseudoh + 0, srcaddr, 4);
102     memcpy(pseudoh + 4, dstaddr, 4);
103     pseudoh[8] = 0x00;
104     pseudoh[9] = udpflag? 17 : 6;
105     pseudoh[10] = tcp_len >> 8;
106     pseudoh[11] = tcp_len & 255;
107    
108     for (i=0; i<12; i+=2) {
109     uint16_t w = (pseudoh[i] << 8) + pseudoh[i+1];
110     sum += w;
111     while (sum > 65535) {
112     int to_add = sum >> 16;
113     sum = (sum & 0xffff) + to_add;
114     }
115     }
116    
117     if (tcp_len & 1) {
118     tcp_len ++;
119     pad = 1;
120     }
121    
122     for (i=0; i<tcp_len; i+=2)
123     if (i != chksumoffset) {
124     uint16_t w;
125     if (!pad || i < tcp_len-2)
126     w = (tcp_header[i] << 8) + tcp_header[i+1];
127     else
128     w = (tcp_header[i] << 8) + 0x00;
129     sum += w;
130     while (sum > 65535) {
131     int to_add = sum >> 16;
132     sum = (sum & 0xffff) + to_add;
133     }
134     }
135    
136     sum ^= 0xffff;
137     tcp_header[chksumoffset + 0] = sum >> 8;
138     tcp_header[chksumoffset + 1] = sum & 0xff;
139     }
140    
141    
142     /*
143     * net_ip_icmp():
144     *
145     * Handle an ICMP packet.
146     *
147     * The IP header (at offset 14) could look something like
148     *
149     * ver=45 tos=00 len=0054 id=001a ofs=0000 ttl=ff p=01 sum=a87e
150     * src=0a000005 dst=03050607
151     *
152     * and the ICMP specific data (beginning at offset 34):
153     *
154     * type=08 code=00 chksum=b8bf
155     * 000c0008d5cee94089190c0008090a0b
156     * 0c0d0e0f101112131415161718191a1b
157     * 1c1d1e1f202122232425262728292a2b
158     * 2c2d2e2f3031323334353637
159     */
160     static void net_ip_icmp(struct net *net, void *extra,
161     unsigned char *packet, int len)
162     {
163     int type;
164     struct ethernet_packet_link *lp;
165    
166     type = packet[34];
167    
168     switch (type) {
169     case 8: /* ECHO request */
170     debug("[ ICMP echo ]\n");
171     lp = net_allocate_ethernet_packet_link(net, extra, len);
172    
173     /* Copy the old packet first: */
174     memcpy(lp->data + 12, packet + 12, len - 12);
175    
176     /* Switch to and from ethernet addresses: */
177     memcpy(lp->data + 0, packet + 6, 6);
178     memcpy(lp->data + 6, packet + 0, 6);
179    
180     /* Switch to and from IP addresses: */
181     memcpy(lp->data + 26, packet + 30, 4);
182     memcpy(lp->data + 30, packet + 26, 4);
183    
184     /* Change from echo REQUEST to echo REPLY: */
185     lp->data[34] = 0x00;
186    
187     /* Decrease the TTL to a low value: */
188     lp->data[22] = 2;
189    
190     /* Recalculate ICMP checksum: */
191     net_ip_checksum(lp->data + 34, 2, len - 34);
192    
193     /* Recalculate IP header checksum: */
194     net_ip_checksum(lp->data + 14, 10, 20);
195    
196     break;
197     default:
198     fatal("[ net: ICMP type %i not yet implemented ]\n", type);
199     }
200     }
201    
202    
203     /*
204     * tcp_closeconnection():
205     *
206     * Helper function which closes down a TCP connection completely.
207     */
208     static void tcp_closeconnection(struct net *net, int con_id)
209     {
210     close(net->tcp_connections[con_id].socket);
211     net->tcp_connections[con_id].state = TCP_OUTSIDE_DISCONNECTED;
212     net->tcp_connections[con_id].in_use = 0;
213     net->tcp_connections[con_id].incoming_buf_len = 0;
214     }
215    
216    
217     /*
218     * net_ip_tcp_connectionreply():
219     *
220     * When changing from state _TRYINGTOCONNECT to _CONNECTED, then this
221     * function should be called with connecting set to 1.
222     *
223     * To send a generic ack reply, set connecting to 0.
224     *
225     * To send data (PSH), set data to non-NULL and datalen to the length.
226     *
227     * This creates an ethernet packet for the guest OS with an ACK to the
228     * initial SYN packet.
229     */
230     void net_ip_tcp_connectionreply(struct net *net, void *extra,
231     int con_id, int connecting, unsigned char *data, int datalen, int rst)
232     {
233     struct ethernet_packet_link *lp;
234     int tcp_length, ip_len, option_len = 20;
235    
236     if (connecting)
237     net->tcp_connections[con_id].outside_acknr =
238     net->tcp_connections[con_id].inside_seqnr + 1;
239    
240     net->tcp_connections[con_id].tcp_id ++;
241     tcp_length = 20 + option_len + datalen;
242     ip_len = 20 + tcp_length;
243     lp = net_allocate_ethernet_packet_link(net, extra, 14 + ip_len);
244    
245     /* Ethernet header: */
246     memcpy(lp->data + 0, net->tcp_connections[con_id].ethernet_address, 6);
247     memcpy(lp->data + 6, net->gateway_ethernet_addr, 6);
248     lp->data[12] = 0x08; /* IP = 0x0800 */
249     lp->data[13] = 0x00;
250    
251     /* IP header: */
252     lp->data[14] = 0x45; /* ver */
253     lp->data[15] = 0x10; /* tos */
254     lp->data[16] = ip_len >> 8;
255     lp->data[17] = ip_len & 0xff;
256     lp->data[18] = net->tcp_connections[con_id].tcp_id >> 8;
257     lp->data[19] = net->tcp_connections[con_id].tcp_id & 0xff;
258     lp->data[20] = 0x40; /* don't fragment */
259     lp->data[21] = 0x00;
260     lp->data[22] = 0x40; /* ttl */
261     lp->data[23] = 6; /* p = TCP */
262     memcpy(lp->data + 26, net->tcp_connections[con_id].
263     outside_ip_address, 4);
264     memcpy(lp->data + 30, net->tcp_connections[con_id].
265     inside_ip_address, 4);
266     net_ip_checksum(lp->data + 14, 10, 20);
267    
268     /* TCP header and options at offset 34: */
269     lp->data[34] = net->tcp_connections[con_id].outside_tcp_port >> 8;
270     lp->data[35] = net->tcp_connections[con_id].outside_tcp_port & 0xff;
271     lp->data[36] = net->tcp_connections[con_id].inside_tcp_port >> 8;
272     lp->data[37] = net->tcp_connections[con_id].inside_tcp_port & 0xff;
273     lp->data[38] = (net->tcp_connections[con_id].
274     outside_seqnr >> 24) & 0xff;
275     lp->data[39] = (net->tcp_connections[con_id].
276     outside_seqnr >> 16) & 0xff;
277     lp->data[40] = (net->tcp_connections[con_id].
278     outside_seqnr >> 8) & 0xff;
279     lp->data[41] = net->tcp_connections[con_id].
280     outside_seqnr & 0xff;
281     lp->data[42] = (net->tcp_connections[con_id].
282     outside_acknr >> 24) & 0xff;
283     lp->data[43] = (net->tcp_connections[con_id].
284     outside_acknr >> 16) & 0xff;
285     lp->data[44] = (net->tcp_connections[con_id].
286     outside_acknr >> 8) & 0xff;
287     lp->data[45] = net->tcp_connections[con_id].outside_acknr & 0xff;
288    
289     /* Control */
290     lp->data[46] = (option_len + 20) / 4 * 0x10;
291     lp->data[47] = 0x10; /* ACK */
292     if (connecting)
293     lp->data[47] |= 0x02; /* SYN */
294     if (net->tcp_connections[con_id].state == TCP_OUTSIDE_CONNECTED)
295     lp->data[47] |= 0x08; /* PSH */
296     if (rst)
297     lp->data[47] |= 0x04; /* RST */
298     if (net->tcp_connections[con_id].state >= TCP_OUTSIDE_DISCONNECTED)
299     lp->data[47] |= 0x01; /* FIN */
300    
301     /* Window */
302     lp->data[48] = 0x10;
303     lp->data[49] = 0x00;
304    
305     /* no urgent ptr */
306    
307     /* options */
308     /* TODO: HAHA, this is ugly */
309     lp->data[54] = 0x02;
310     lp->data[55] = 0x04;
311     lp->data[56] = 0x05;
312     lp->data[57] = 0xb4;
313     lp->data[58] = 0x01;
314     lp->data[59] = 0x03;
315     lp->data[60] = 0x03;
316     lp->data[61] = 0x00;
317     lp->data[62] = 0x01;
318     lp->data[63] = 0x01;
319     lp->data[64] = 0x08;
320     lp->data[65] = 0x0a;
321     lp->data[66] = (net->timestamp >> 24) & 0xff;
322     lp->data[67] = (net->timestamp >> 16) & 0xff;
323     lp->data[68] = (net->timestamp >> 8) & 0xff;
324     lp->data[69] = net->timestamp & 0xff;
325     lp->data[70] = (net->tcp_connections[con_id].
326     inside_timestamp >> 24) & 0xff;
327     lp->data[71] = (net->tcp_connections[con_id].
328     inside_timestamp >> 16) & 0xff;
329     lp->data[72] = (net->tcp_connections[con_id].
330     inside_timestamp >> 8) & 0xff;
331     lp->data[73] = net->tcp_connections[con_id].
332     inside_timestamp & 0xff;
333    
334     /* data: */
335     if (data != NULL) {
336     memcpy(lp->data + 74, data, datalen);
337     net->tcp_connections[con_id].outside_seqnr += datalen;
338     }
339    
340     /* Checksum: */
341     net_ip_tcp_checksum(lp->data + 34, 16, tcp_length,
342     lp->data + 26, lp->data + 30, 0);
343    
344     #if 0
345     {
346     int i;
347     fatal("[ net_ip_tcp_connectionreply(%i): ", connecting);
348     for (i=0; i<ip_len+14; i++)
349     fatal("%02x", lp->data[i]);
350     fatal(" ]\n");
351     }
352     #endif
353    
354     if (connecting)
355     net->tcp_connections[con_id].outside_seqnr ++;
356     }
357    
358    
359     /*
360     * net_ip_tcp():
361     *
362     * Handle a TCP packet comming from the emulated OS.
363     *
364     * The IP header (at offset 14) could look something like
365     *
366     * ver=45 tos=00 len=003c id=0006 ofs=0000 ttl=40 p=11 sum=b798
367     * src=0a000001 dst=c1abcdef
368     *
369     * TCP header, at offset 34:
370     *
371     * srcport=fffe dstport=0015 seqnr=af419a1d acknr=00000000
372     * control=a002 window=4000 checksum=fe58 urgent=0000
373     * and then "options and padding" and then data.
374     * (020405b4010303000101080a0000000000000000)
375     *
376     * See the following URLs for good descriptions of TCP:
377     *
378     * http://www.networksorcery.com/enp/protocol/tcp.htm
379     * http://www.tcpipguide.com/free/t_TCPIPTransmissionControlProtocolTCP.htm
380     */
381     static void net_ip_tcp(struct net *net, void *extra,
382     unsigned char *packet, int len)
383     {
384     int con_id, free_con_id, i, res;
385     int srcport, dstport, data_offset, window, checksum, urgptr;
386     int syn, ack, psh, rst, urg, fin;
387     uint32_t seqnr, acknr;
388     struct sockaddr_in remote_ip;
389     fd_set rfds;
390     struct timeval tv;
391     int send_ofs;
392    
393     #if 0
394     fatal("[ net: TCP: ");
395     for (i=0; i<26; i++)
396     fatal("%02x", packet[i]);
397     fatal(" ");
398     #endif
399    
400     srcport = (packet[34] << 8) + packet[35];
401     dstport = (packet[36] << 8) + packet[37];
402    
403     seqnr = (packet[38] << 24) + (packet[39] << 16)
404     + (packet[40] << 8) + packet[41];
405     acknr = (packet[42] << 24) + (packet[43] << 16)
406     + (packet[44] << 8) + packet[45];
407    
408     #if 0
409     fatal("%i.%i.%i.%i:%i -> %i.%i.%i.%i:%i, seqnr=%lli acknr=%lli ",
410     packet[26], packet[27], packet[28], packet[29], srcport,
411     packet[30], packet[31], packet[32], packet[33], dstport,
412     (long long)seqnr, (long long)acknr);
413     #endif
414    
415     data_offset = (packet[46] >> 4) * 4 + 34;
416     /* data_offset is now data offset within packet :-) */
417    
418     urg = packet[47] & 32;
419     ack = packet[47] & 16;
420     psh = packet[47] & 8;
421     rst = packet[47] & 4;
422     syn = packet[47] & 2;
423     fin = packet[47] & 1;
424     window = (packet[48] << 8) + packet[49];
425     checksum = (packet[50] << 8) + packet[51];
426     urgptr = (packet[52] << 8) + packet[53];
427    
428     #if 0
429     fatal(urg? "URG " : "");
430     fatal(ack? "ACK " : "");
431     fatal(psh? "PSH " : "");
432     fatal(rst? "RST " : "");
433     fatal(syn? "SYN " : "");
434     fatal(fin? "FIN " : "");
435    
436     fatal("window=0x%04x checksum=0x%04x urgptr=0x%04x ",
437     window, checksum, urgptr);
438    
439     fatal("options=");
440     for (i=34+20; i<data_offset; i++)
441     fatal("%02x", packet[i]);
442    
443     fatal(" data=");
444     for (i=data_offset; i<len; i++)
445     fatal("%02x", packet[i]);
446    
447     fatal(" ]\n");
448     #endif
449    
450     net_ip_tcp_checksum(packet + 34, 16, len - 34,
451     packet + 26, packet + 30, 0);
452     if (packet[50] * 256 + packet[51] != checksum) {
453     debug("TCP: dropping packet because of checksum mismatch "
454     "(0x%04x != 0x%04x)\n", packet[50] * 256 + packet[51],
455     checksum);
456    
457     return;
458     }
459    
460     /* Does this packet belong to a current connection? */
461     con_id = free_con_id = -1;
462     for (i=0; i<MAX_TCP_CONNECTIONS; i++) {
463     if (!net->tcp_connections[i].in_use)
464     free_con_id = i;
465     if (net->tcp_connections[i].in_use &&
466     net->tcp_connections[i].inside_tcp_port == srcport &&
467     net->tcp_connections[i].outside_tcp_port == dstport &&
468     memcmp(net->tcp_connections[i].inside_ip_address,
469     packet + 26, 4) == 0 &&
470     memcmp(net->tcp_connections[i].outside_ip_address,
471     packet + 30, 4) == 0) {
472     con_id = i;
473     break;
474     }
475     }
476    
477     /*
478     * Unknown connection, and not SYN? Then drop the packet.
479     * TODO: Send back RST?
480     */
481     if (con_id < 0 && !syn) {
482     debug("[ net: TCP: dropping packet from unknown connection,"
483     " %i.%i.%i.%i:%i -> %i.%i.%i.%i:%i %s%s%s%s%s]\n",
484     packet[26], packet[27], packet[28], packet[29], srcport,
485     packet[30], packet[31], packet[32], packet[33], dstport,
486     fin? "FIN ": "", syn? "SYN ": "", ack? "ACK ": "",
487     psh? "PSH ": "", rst? "RST ": "");
488     return;
489     }
490    
491     /* Known connection, and SYN? Then ignore the packet. */
492     if (con_id >= 0 && syn) {
493     debug("[ net: TCP: ignoring redundant SYN packet from known"
494     " connection, %i.%i.%i.%i:%i -> %i.%i.%i.%i:%i ]\n",
495     packet[26], packet[27], packet[28], packet[29], srcport,
496     packet[30], packet[31], packet[32], packet[33], dstport);
497     return;
498     }
499    
500     /*
501     * A new outgoing connection?
502     */
503     if (con_id < 0 && syn) {
504     debug("[ net: TCP: new outgoing connection, %i.%i.%i.%i:%i"
505     " -> %i.%i.%i.%i:%i ]\n",
506     packet[26], packet[27], packet[28], packet[29], srcport,
507     packet[30], packet[31], packet[32], packet[33], dstport);
508    
509     /* Find a free connection id to use: */
510     if (free_con_id < 0) {
511     #if 1
512     /*
513     * TODO: Reuse the oldest one currently in use, or
514     * just drop the new connection attempt? Drop for now.
515     */
516     fatal("[ TOO MANY TCP CONNECTIONS IN USE! "
517     "Increase MAX_TCP_CONNECTIONS! ]\n");
518     return;
519     #else
520     int i;
521     int64_t oldest = net->
522     tcp_connections[0].last_used_timestamp;
523     free_con_id = 0;
524    
525     fatal("[ NO FREE TCP SLOTS, REUSING OLDEST ONE ]\n");
526     for (i=0; i<MAX_TCP_CONNECTIONS; i++)
527     if (net->tcp_connections[i].
528     last_used_timestamp < oldest) {
529     oldest = net->tcp_connections[i].
530     last_used_timestamp;
531     free_con_id = i;
532     }
533     tcp_closeconnection(net, free_con_id);
534     #endif
535     }
536    
537     con_id = free_con_id;
538     memset(&net->tcp_connections[con_id], 0,
539     sizeof(struct tcp_connection));
540    
541     memcpy(net->tcp_connections[con_id].ethernet_address,
542     packet + 6, 6);
543     memcpy(net->tcp_connections[con_id].inside_ip_address,
544     packet + 26, 4);
545     net->tcp_connections[con_id].inside_tcp_port = srcport;
546     memcpy(net->tcp_connections[con_id].outside_ip_address,
547     packet + 30, 4);
548     net->tcp_connections[con_id].outside_tcp_port = dstport;
549    
550     net->tcp_connections[con_id].socket =
551     socket(AF_INET, SOCK_STREAM, 0);
552     if (net->tcp_connections[con_id].socket < 0) {
553     fatal("[ net: TCP: socket() returned %i ]\n",
554     net->tcp_connections[con_id].socket);
555     return;
556     }
557    
558     debug("[ new tcp outgoing socket=%i ]\n",
559     net->tcp_connections[con_id].socket);
560    
561     net->tcp_connections[con_id].in_use = 1;
562    
563     /* Set the socket to non-blocking: */
564     res = fcntl(net->tcp_connections[con_id].socket, F_GETFL);
565     fcntl(net->tcp_connections[con_id].socket, F_SETFL,
566     res | O_NONBLOCK);
567    
568     remote_ip.sin_family = AF_INET;
569     memcpy((unsigned char *)&remote_ip.sin_addr,
570     net->tcp_connections[con_id].outside_ip_address, 4);
571     remote_ip.sin_port = htons(
572     net->tcp_connections[con_id].outside_tcp_port);
573    
574     res = connect(net->tcp_connections[con_id].socket,
575     (struct sockaddr *)&remote_ip, sizeof(remote_ip));
576    
577     /* connect can return -1, and errno = EINPROGRESS
578     as we might not have connected right away. */
579    
580     net->tcp_connections[con_id].state =
581     TCP_OUTSIDE_TRYINGTOCONNECT;
582    
583     net->tcp_connections[con_id].outside_acknr = 0;
584     net->tcp_connections[con_id].outside_seqnr =
585     ((random() & 0xffff) << 16) + (random() & 0xffff);
586     }
587    
588     if (rst) {
589     debug("[ 'rst': disconnecting TCP connection %i ]\n", con_id);
590     net_ip_tcp_connectionreply(net, extra, con_id, 0, NULL, 0, 1);
591     tcp_closeconnection(net, con_id);
592     return;
593     }
594    
595     if (ack && net->tcp_connections[con_id].state
596     == TCP_OUTSIDE_DISCONNECTED2) {
597     debug("[ 'ack': guestOS's final termination of TCP "
598     "connection %i ]\n", con_id);
599    
600     /* Send an RST? (TODO, this is wrong...) */
601     net_ip_tcp_connectionreply(net, extra, con_id, 0, NULL, 0, 1);
602    
603     /* ... and forget about this connection: */
604     tcp_closeconnection(net, con_id);
605     return;
606     }
607    
608     if (fin && net->tcp_connections[con_id].state
609     == TCP_OUTSIDE_DISCONNECTED) {
610     debug("[ 'fin': response to outside's disconnection of "
611     "TCP connection %i ]\n", con_id);
612    
613     /* Send an ACK: */
614     net->tcp_connections[con_id].state = TCP_OUTSIDE_CONNECTED;
615     net_ip_tcp_connectionreply(net, extra, con_id, 0, NULL, 0, 0);
616     net->tcp_connections[con_id].state = TCP_OUTSIDE_DISCONNECTED2;
617     return;
618     }
619    
620     if (fin) {
621     debug("[ 'fin': guestOS disconnecting TCP connection %i ]\n",
622     con_id);
623    
624     /* Send ACK: */
625     net_ip_tcp_connectionreply(net, extra, con_id, 0, NULL, 0, 0);
626     net->tcp_connections[con_id].state = TCP_OUTSIDE_DISCONNECTED2;
627    
628     /* Return and send FIN: */
629     goto ret;
630     }
631    
632     if (ack) {
633     debug("ACK %i bytes, inside_acknr=%u outside_seqnr=%u\n",
634     net->tcp_connections[con_id].incoming_buf_len,
635     net->tcp_connections[con_id].inside_acknr,
636     net->tcp_connections[con_id].outside_seqnr);
637     net->tcp_connections[con_id].inside_acknr = acknr;
638     if (net->tcp_connections[con_id].inside_acknr ==
639     net->tcp_connections[con_id].outside_seqnr &&
640     net->tcp_connections[con_id].incoming_buf_len != 0) {
641     debug(" all acked\n");
642     net->tcp_connections[con_id].incoming_buf_len = 0;
643     }
644     }
645    
646     net->tcp_connections[con_id].inside_seqnr = seqnr;
647    
648     /* TODO: This is hardcoded for a specific NetBSD packet: */
649     if (packet[34 + 30] == 0x08 && packet[34 + 31] == 0x0a)
650     net->tcp_connections[con_id].inside_timestamp =
651     (packet[34 + 32 + 0] << 24) +
652     (packet[34 + 32 + 1] << 16) +
653     (packet[34 + 32 + 2] << 8) +
654     (packet[34 + 32 + 3] << 0);
655    
656    
657     net->timestamp ++;
658     net->tcp_connections[con_id].last_used_timestamp = net->timestamp;
659    
660    
661     if (net->tcp_connections[con_id].state != TCP_OUTSIDE_CONNECTED) {
662     debug("[ not connected to outside ]\n");
663     return;
664     }
665    
666    
667     if (data_offset >= len)
668     return;
669    
670    
671     /*
672     * We are here if this is a known connection, and data is to be
673     * transmitted to the outside world.
674     */
675    
676     send_ofs = data_offset;
677     send_ofs += ((int32_t)net->tcp_connections[con_id].outside_acknr
678     - (int32_t)seqnr);
679     #if 1
680     debug("[ %i bytes of tcp data to be sent, beginning at seqnr %u, ",
681     len - data_offset, seqnr);
682     debug("outside is at acknr %u ==> %i actual bytes to be sent ]\n",
683     net->tcp_connections[con_id].outside_acknr, len - send_ofs);
684     #endif
685    
686     /* Drop outgoing packet if the guest OS' seqnr is not
687     the same as we have acked. (We have missed something, perhaps.) */
688     if (seqnr != net->tcp_connections[con_id].outside_acknr) {
689     debug("!! outgoing TCP packet dropped (seqnr = %u, "
690     "outside_acknr = %u)\n", seqnr,
691     net->tcp_connections[con_id].outside_acknr);
692     goto ret;
693     }
694    
695     if (len - send_ofs > 0) {
696     /* Is the socket available for output? */
697     FD_ZERO(&rfds); /* write */
698     FD_SET(net->tcp_connections[con_id].socket, &rfds);
699     tv.tv_sec = tv.tv_usec = 0;
700     errno = 0;
701     res = select(net->tcp_connections[con_id].socket+1,
702     NULL, &rfds, NULL, &tv);
703     if (res < 1) {
704     net->tcp_connections[con_id].state =
705     TCP_OUTSIDE_DISCONNECTED;
706     debug("[ TCP: disconnect on select for writing ]\n");
707     goto ret;
708     }
709    
710     res = write(net->tcp_connections[con_id].socket,
711     packet + send_ofs, len - send_ofs);
712    
713     if (res > 0) {
714     net->tcp_connections[con_id].outside_acknr += res;
715     } else if (errno == EAGAIN) {
716     /* Just ignore this attempt. */
717     return;
718     } else {
719     debug("[ error writing %i bytes to TCP connection %i:"
720     " errno = %i ]\n", len - send_ofs, con_id, errno);
721     net->tcp_connections[con_id].state =
722     TCP_OUTSIDE_DISCONNECTED;
723     debug("[ TCP: disconnect on write() ]\n");
724     goto ret;
725     }
726     }
727    
728     ret:
729     /* Send an ACK (or FIN) to the guest OS: */
730     net_ip_tcp_connectionreply(net, extra, con_id, 0, NULL, 0, 0);
731     }
732    
733    
734     /*
735     * net_ip_udp():
736     *
737     * Handle a UDP packet.
738     *
739     * (See http://www.networksorcery.com/enp/protocol/udp.htm.)
740     *
741     * The IP header (at offset 14) could look something like
742     *
743     * ver=45 tos=00 len=003c id=0006 ofs=0000 ttl=40 p=11 sum=b798
744     * src=0a000001 dst=c1abcdef
745     *
746     * and the UDP data (beginning at offset 34):
747     *
748     * srcport=fffc dstport=0035 length=0028 chksum=76b6
749     * 43e20100000100000000000003667470066e6574627364036f726700001c0001
750     */
751     static void net_ip_udp(struct net *net, void *extra,
752     unsigned char *packet, int len)
753     {
754     int con_id, free_con_id, i, srcport, dstport, udp_len;
755     ssize_t res;
756     struct sockaddr_in remote_ip;
757    
758     if ((packet[20] & 0x3f) != 0) {
759     fatal("[ net_ip_udp(): WARNING! fragmented UDP "
760     "packet, TODO ]\n");
761     return;
762     }
763    
764     srcport = (packet[34] << 8) + packet[35];
765     dstport = (packet[36] << 8) + packet[37];
766     udp_len = (packet[38] << 8) + packet[39];
767     /* chksum at offset 40 and 41 */
768    
769     debug("[ net: UDP: ");
770     debug("srcport=%i dstport=%i len=%i ", srcport, dstport, udp_len);
771     for (i=42; i<len; i++) {
772     if (packet[i] >= ' ' && packet[i] < 127)
773     debug("%c", packet[i]);
774     else
775     debug("[%02x]", packet[i]);
776     }
777     debug(" ]\n");
778    
779     /* Is this "connection" new, or a currently ongoing one? */
780     con_id = free_con_id = -1;
781     for (i=0; i<MAX_UDP_CONNECTIONS; i++) {
782     if (!net->udp_connections[i].in_use)
783     free_con_id = i;
784     if (net->udp_connections[i].in_use &&
785     net->udp_connections[i].inside_udp_port == srcport &&
786     net->udp_connections[i].outside_udp_port == dstport &&
787     memcmp(net->udp_connections[i].inside_ip_address,
788     packet + 26, 4) == 0 &&
789     memcmp(net->udp_connections[i].outside_ip_address,
790     packet + 30, 4) == 0) {
791     con_id = i;
792     break;
793     }
794     }
795    
796     debug("&& UDP connection is ");
797     if (con_id >= 0)
798     debug("ONGOING");
799     else {
800     debug("NEW");
801     if (free_con_id < 0) {
802     int i;
803     int64_t oldest = net->
804     udp_connections[0].last_used_timestamp;
805     free_con_id = 0;
806    
807     debug(", NO FREE SLOTS, REUSING OLDEST ONE");
808     for (i=0; i<MAX_UDP_CONNECTIONS; i++)
809     if (net->udp_connections[i].
810     last_used_timestamp < oldest) {
811     oldest = net->udp_connections[i].
812     last_used_timestamp;
813     free_con_id = i;
814     }
815     close(net->udp_connections[free_con_id].socket);
816     }
817     con_id = free_con_id;
818     memset(&net->udp_connections[con_id], 0,
819     sizeof(struct udp_connection));
820    
821     memcpy(net->udp_connections[con_id].ethernet_address,
822     packet + 6, 6);
823     memcpy(net->udp_connections[con_id].inside_ip_address,
824     packet + 26, 4);
825     net->udp_connections[con_id].inside_udp_port = srcport;
826     memcpy(net->udp_connections[con_id].outside_ip_address,
827     packet + 30, 4);
828     net->udp_connections[con_id].outside_udp_port = dstport;
829    
830     net->udp_connections[con_id].socket = socket(AF_INET,
831     SOCK_DGRAM, 0);
832     if (net->udp_connections[con_id].socket < 0) {
833     fatal("[ net: UDP: socket() returned %i ]\n",
834     net->udp_connections[con_id].socket);
835     return;
836     }
837    
838     debug(" {socket=%i}", net->udp_connections[con_id].socket);
839    
840     net->udp_connections[con_id].in_use = 1;
841    
842     /* Set the socket to non-blocking: */
843     res = fcntl(net->udp_connections[con_id].socket, F_GETFL);
844     fcntl(net->udp_connections[con_id].socket, F_SETFL,
845     res | O_NONBLOCK);
846     }
847    
848     debug(", connection id %i\n", con_id);
849    
850     net->timestamp ++;
851     net->udp_connections[con_id].last_used_timestamp = net->timestamp;
852    
853     remote_ip.sin_family = AF_INET;
854     memcpy((unsigned char *)&remote_ip.sin_addr,
855     net->udp_connections[con_id].outside_ip_address, 4);
856    
857     /*
858     * Special case for the nameserver: If a UDP packet is sent to
859     * the gateway, it will be forwarded to the nameserver, if it is
860     * known.
861     */
862     if (net->nameserver_known &&
863     memcmp(net->udp_connections[con_id].outside_ip_address,
864     &net->gateway_ipv4_addr[0], 4) == 0) {
865     memcpy((unsigned char *)&remote_ip.sin_addr,
866     &net->nameserver_ipv4, 4);
867     net->udp_connections[con_id].fake_ns = 1;
868     }
869    
870     remote_ip.sin_port = htons(
871     net->udp_connections[con_id].outside_udp_port);
872    
873     res = sendto(net->udp_connections[con_id].socket, packet + 42,
874     len - 42, 0, (const struct sockaddr *)&remote_ip,
875     sizeof(remote_ip));
876    
877     if (res != len-42)
878     debug("[ net: UDP: unable to send %i bytes ]\n", len-42);
879     else
880     debug("[ net: UDP: OK!!! ]\n");
881     }
882    
883    
884     /*
885     * net_ip():
886     *
887     * Handle an IP packet, coming from the emulated NIC.
888     */
889     void net_ip(struct net *net, void *extra, unsigned char *packet, int len)
890     {
891     #if 1
892     int i;
893    
894     debug("[ net: IP: ");
895     debug("ver=%02x ", packet[14]);
896     debug("tos=%02x ", packet[15]);
897     debug("len=%02x%02x ", packet[16], packet[17]);
898     debug("id=%02x%02x ", packet[18], packet[19]);
899     debug("ofs=%02x%02x ", packet[20], packet[21]);
900     debug("ttl=%02x ", packet[22]);
901     debug("p=%02x ", packet[23]);
902     debug("sum=%02x%02x ", packet[24], packet[25]);
903     debug("src=%02x%02x%02x%02x ",
904     packet[26], packet[27], packet[28], packet[29]);
905     debug("dst=%02x%02x%02x%02x ",
906     packet[30], packet[31], packet[32], packet[33]);
907     for (i=34; i<len; i++)
908     debug("%02x", packet[i]);
909     debug(" ]\n");
910     #endif
911    
912     /* Cut off overflowing tail data: */
913     if (len > 14 + packet[16]*256 + packet[17])
914     len = 14 + packet[16]*256 + packet[17];
915    
916     if (packet[14] == 0x45) {
917     /* IPv4: */
918     switch (packet[23]) {
919     case 1: /* ICMP */
920     net_ip_icmp(net, extra, packet, len);
921     break;
922     case 6: /* TCP */
923     net_ip_tcp(net, extra, packet, len);
924     break;
925     case 17:/* UDP */
926     net_ip_udp(net, extra, packet, len);
927     break;
928     default:
929     fatal("[ net: IP: UNIMPLEMENTED protocol %i ]\n",
930     packet[23]);
931     }
932     } else
933     fatal("[ net: IP: UNIMPLEMENTED ip, first byte = 0x%02x ]\n",
934     packet[14]);
935     }
936    
937    
938     /*
939     * net_ip_broadcast_dhcp():
940     *
941     * Handle an IPv4 DHCP broadcast packet, coming from the emulated NIC.
942     *
943     * Read http://www.ietf.org/rfc/rfc2131.txt for details on DHCP.
944     * (And http://users.telenet.be/mydotcom/library/network/dhcp.htm.)
945     */
946     static void net_ip_broadcast_dhcp(struct net *net, void *extra,
947     unsigned char *packet, int len)
948     {
949     /*
950     * TODO
951     */
952     #if 1
953     struct ethernet_packet_link *lp;
954     int i;
955    
956     fatal("[ net: IPv4 DHCP: ");
957     #if 1
958     fatal("ver=%02x ", packet[14]);
959     fatal("tos=%02x ", packet[15]);
960     fatal("len=%02x%02x ", packet[16], packet[17]);
961     fatal("id=%02x%02x ", packet[18], packet[19]);
962     fatal("ofs=%02x%02x ", packet[20], packet[21]);
963     fatal("ttl=%02x ", packet[22]);
964     fatal("p=%02x ", packet[23]);
965     fatal("sum=%02x%02x ", packet[24], packet[25]);
966     #endif
967     fatal("src=%02x%02x%02x%02x ",
968     packet[26], packet[27], packet[28], packet[29]);
969     fatal("dst=%02x%02x%02x%02x ",
970     packet[30], packet[31], packet[32], packet[33]);
971     #if 0
972     for (i=34; i<len; i++)
973     fatal("%02x", packet[i]);
974     #endif
975    
976     if (len < 34 + 8 + 236) {
977     fatal("[ DHCP packet too short? Len=%i ]\n", len);
978     return;
979     }
980    
981     /*
982     * UDP data (at offset 34):
983     *
984     * srcport=0044 dstport=0043 length=0134 chksum=a973
985     * data = 01010600d116d276000000000000000000000000000000
986     * 0000000000102030405060...0000...638253633501...000
987     */
988    
989     fatal("op=%02x ", packet[42]);
990     fatal("htype=%02x ", packet[43]);
991     fatal("hlen=%02x ", packet[44]);
992     fatal("hops=%02x ", packet[45]);
993     fatal("xid=%02x%02x%02x%02x ", packet[46], packet[47],
994     packet[48], packet[49]);
995     fatal("secs=%02x%02x ", packet[50], packet[51]);
996     fatal("flags=%02x%02x ", packet[52], packet[53]);
997     fatal("ciaddr=%02x%02x%02x%02x ", packet[54], packet[55],
998     packet[56], packet[57]);
999     fatal("yiaddr=%02x%02x%02x%02x ", packet[58], packet[59],
1000     packet[60], packet[61]);
1001     fatal("siaddr=%02x%02x%02x%02x ", packet[62], packet[63],
1002     packet[64], packet[65]);
1003     fatal("giaddr=%02x%02x%02x%02x ", packet[66], packet[67],
1004     packet[68], packet[69]);
1005     fatal("chaddr=");
1006     for (i=70; i<70+16; i++)
1007     fatal("%02x", packet[i]);
1008     /*
1009     | sname (64) |
1010     | file (128) |
1011     */
1012     fatal(" ]\n");
1013    
1014     lp = net_allocate_ethernet_packet_link(net, extra, len);
1015    
1016     /* Copy the old packet first: */
1017     memcpy(lp->data, packet, len);
1018    
1019     /* We are sending to the client, from the gateway: */
1020     memcpy(lp->data + 0, packet + 6, 6);
1021     memcpy(lp->data + 6, net->gateway_ethernet_addr, 6);
1022    
1023     memcpy(lp->data + 26, &net->gateway_ipv4_addr[0], 4);
1024     lp->data[30] = 0xff;
1025     lp->data[31] = 0xff;
1026     lp->data[32] = 0xff;
1027     lp->data[33] = 0xff;
1028    
1029     /* Switch src and dst ports: */
1030     memcpy(lp->data + 34, packet + 36, 2);
1031     memcpy(lp->data + 36, packet + 34, 2);
1032    
1033     /* Client's (yiaddr) IPv4 address: */
1034     lp->data[58] = 10;
1035     lp->data[59] = 0;
1036     lp->data[60] = 0;
1037     lp->data[61] = 1;
1038    
1039     /* Server's IPv4 address: (giaddr) */
1040     memcpy(lp->data + 66, &net->gateway_ipv4_addr[0], 4);
1041    
1042     /* This is a Reply: */
1043     lp->data[42] = 0x02;
1044    
1045     snprintf((char *)lp->data + 70+16+64, 8, "gxemul");
1046    
1047     /* Recalculate IP header checksum: */
1048     net_ip_checksum(lp->data + 14, 10, 20);
1049    
1050     /* ... and the UDP checksum: */
1051     net_ip_tcp_checksum(lp->data + 34, 6, len - 34 - 8,
1052     lp->data + 26, lp->data + 30, 1);
1053    
1054    
1055     /* Debug dump: */
1056     packet = lp->data;
1057     fatal("[ net: IPv4 DHCP REPLY: ");
1058     for (i=0; i<14; i++)
1059     fatal("%02x", packet[i]);
1060     fatal("ver=%02x ", packet[14]);
1061     fatal("tos=%02x ", packet[15]);
1062     fatal("len=%02x%02x ", packet[16], packet[17]);
1063     fatal("id=%02x%02x ", packet[18], packet[19]);
1064     fatal("ofs=%02x%02x ", packet[20], packet[21]);
1065     fatal("ttl=%02x ", packet[22]);
1066     fatal("p=%02x ", packet[23]);
1067     fatal("sum=%02x%02x ", packet[24], packet[25]);
1068     fatal("src=%02x%02x%02x%02x ",
1069     packet[26], packet[27], packet[28], packet[29]);
1070     fatal("dst=%02x%02x%02x%02x ",
1071     packet[30], packet[31], packet[32], packet[33]);
1072     fatal("op=%02x ", packet[42]);
1073     fatal("htype=%02x ", packet[43]);
1074     fatal("hlen=%02x ", packet[44]);
1075     fatal("hops=%02x ", packet[45]);
1076     fatal("xid=%02x%02x%02x%02x ", packet[46], packet[47],
1077     packet[48], packet[49]);
1078     fatal("secs=%02x%02x ", packet[50], packet[51]);
1079     fatal("flags=%02x%02x ", packet[52], packet[53]);
1080     fatal("ciaddr=%02x%02x%02x%02x ", packet[54], packet[55],
1081     packet[56], packet[57]);
1082     fatal("yiaddr=%02x%02x%02x%02x ", packet[58], packet[59],
1083     packet[60], packet[61]);
1084     fatal("siaddr=%02x%02x%02x%02x ", packet[62], packet[63],
1085     packet[64], packet[65]);
1086     fatal("giaddr=%02x%02x%02x%02x ", packet[66], packet[67],
1087     packet[68], packet[69]);
1088     fatal("chaddr=");
1089     for (i=70; i<70+16; i++)
1090     fatal("%02x", packet[i]);
1091     fatal(" ]\n");
1092    
1093     #endif
1094     }
1095    
1096    
1097     /*
1098     * net_ip_broadcast():
1099     *
1100     * Handle an IP broadcast packet, coming from the emulated NIC.
1101     * (This is usually a DHCP request, or similar.)
1102     */
1103     void net_ip_broadcast(struct net *net, void *extra,
1104     unsigned char *packet, int len)
1105     {
1106     unsigned char *p = (void *) &net->netmask_ipv4;
1107     uint32_t x, y;
1108     int i, xl, warning = 0, match = 0;
1109    
1110     #if 0
1111     fatal("[ net: IP BROADCAST: ");
1112     fatal("ver=%02x ", packet[14]);
1113     fatal("tos=%02x ", packet[15]);
1114     fatal("len=%02x%02x ", packet[16], packet[17]);
1115     fatal("id=%02x%02x ", packet[18], packet[19]);
1116     fatal("ofs=%02x%02x ", packet[20], packet[21]);
1117     fatal("ttl=%02x ", packet[22]);
1118     fatal("p=%02x ", packet[23]);
1119     fatal("sum=%02x%02x ", packet[24], packet[25]);
1120     fatal("src=%02x%02x%02x%02x ",
1121     packet[26], packet[27], packet[28], packet[29]);
1122     fatal("dst=%02x%02x%02x%02x ",
1123     packet[30], packet[31], packet[32], packet[33]);
1124     for (i=34; i<len; i++)
1125     fatal("%02x", packet[i]);
1126     fatal(" ]\n");
1127     #endif
1128    
1129     /* Check for 10.0.0.255 first, maybe some guest OSes think that
1130     it's a /24 network, regardless of what it actually is. */
1131     y = (packet[30] << 24) + (packet[31] << 16) +
1132     (packet[32] << 8) + packet[33];
1133    
1134     x = (p[0] << 24) + (p[1] << 16) + (p[2] << 8) + p[3];
1135     /* Example: x = 10.0.0.0 */
1136     x |= 255;
1137    
1138     if (x == y) {
1139     warning = 1;
1140     match = 1;
1141     }
1142    
1143     xl = 32 - net->netmask_ipv4_len;
1144     x |= (1 << xl) - 1;
1145     /* x = 10.255.255.255 */
1146    
1147     if (x == y)
1148     match = 1;
1149     if (y == 0xffffffff)
1150     match = 1;
1151    
1152     if (warning)
1153     fatal("[ net_ip_broadcast(): warning: broadcast to "
1154     "0x%08x, expecting broadcast to 0x%08x or "
1155     "0xffffffff ]\n", y, x);
1156    
1157     /* Cut off overflowing tail data: */
1158     if (len > 14 + packet[16]*256 + packet[17])
1159     len = 14 + packet[16]*256 + packet[17];
1160    
1161     /* Check for known packets: */
1162     if (packet[14] == 0x45 && /* IPv4 */
1163     packet[23] == 0x11 && /* UDP */
1164     packet[34] == 0 && packet[35] == 68 && /* DHCP client */
1165     packet[36] == 0 && packet[37] == 67) { /* DHCP server */
1166     net_ip_broadcast_dhcp(net, extra, packet, len);
1167     return;
1168     }
1169    
1170     /* Unknown packet: */
1171     fatal("[ net: UNIMPLEMENTED IP BROADCAST: ");
1172     fatal("ver=%02x ", packet[14]);
1173     fatal("tos=%02x ", packet[15]);
1174     fatal("len=%02x%02x ", packet[16], packet[17]);
1175     fatal("id=%02x%02x ", packet[18], packet[19]);
1176     fatal("ofs=%02x%02x ", packet[20], packet[21]);
1177     fatal("ttl=%02x ", packet[22]);
1178     fatal("p=%02x ", packet[23]);
1179     fatal("sum=%02x%02x ", packet[24], packet[25]);
1180     fatal("src=%02x%02x%02x%02x ",
1181     packet[26], packet[27], packet[28], packet[29]);
1182     fatal("dst=%02x%02x%02x%02x ",
1183     packet[30], packet[31], packet[32], packet[33]);
1184     for (i=34; i<len; i++)
1185     fatal("%02x", packet[i]);
1186     fatal(" ]\n");
1187     }
1188    
1189    
1190     /*
1191     * net_udp_rx_avail():
1192     *
1193     * Receive any available UDP packets (from the outside world).
1194     */
1195     void net_udp_rx_avail(struct net *net, void *extra)
1196     {
1197     int received_packets_this_tick = 0;
1198     int max_packets_this_tick = 200;
1199     int con_id;
1200    
1201     for (con_id=0; con_id<MAX_UDP_CONNECTIONS; con_id++) {
1202     ssize_t res;
1203     unsigned char buf[66000];
1204     unsigned char udp_data[66008];
1205     struct sockaddr_in from;
1206     socklen_t from_len = sizeof(from);
1207     int ip_len, udp_len;
1208     struct ethernet_packet_link *lp;
1209     int max_per_packet;
1210     int bytes_converted = 0;
1211     int this_packets_data_length;
1212     int fragment_ofs = 0;
1213    
1214     if (received_packets_this_tick > max_packets_this_tick)
1215     break;
1216    
1217     if (!net->udp_connections[con_id].in_use)
1218     continue;
1219    
1220     if (net->udp_connections[con_id].socket < 0) {
1221     fatal("INTERNAL ERROR in net.c, udp socket < 0 "
1222     "but in use?\n");
1223     continue;
1224     }
1225    
1226     res = recvfrom(net->udp_connections[con_id].socket, buf,
1227     sizeof(buf), 0, (struct sockaddr *)&from, &from_len);
1228    
1229     /* No more incoming UDP on this connection? */
1230     if (res < 0)
1231     continue;
1232    
1233     net->timestamp ++;
1234     net->udp_connections[con_id].last_used_timestamp =
1235     net->timestamp;
1236    
1237     net->udp_connections[con_id].udp_id ++;
1238    
1239     /*
1240     * Special case for the nameserver: If a UDP packet is
1241     * received from the nameserver (if the nameserver's IP is
1242     * known), fake it so that it comes from the gateway instead.
1243     */
1244     if (net->udp_connections[con_id].fake_ns)
1245     memcpy(((unsigned char *)(&from))+4,
1246     &net->gateway_ipv4_addr[0], 4);
1247    
1248     /*
1249     * We now have a UDP packet of size 'res' which we need
1250     * turn into one or more ethernet packets for the emulated
1251     * operating system. Ethernet packets are at most 1518
1252     * bytes long. With some margin, that means we can have
1253     * about 1500 bytes per packet.
1254     *
1255     * Ethernet = 14 bytes
1256     * IP = 20 bytes
1257     * (UDP = 8 bytes + data)
1258     *
1259     * So data can be at most max_per_packet - 34. For UDP
1260     * fragments, each multiple should (?) be a multiple of
1261     * 8 bytes, except the last which doesn't have any such
1262     * restriction.
1263     */
1264     max_per_packet = 1500;
1265    
1266     /* UDP: */
1267     udp_len = res + 8;
1268     /* from[2..3] = outside_udp_port */
1269     udp_data[0] = ((unsigned char *)&from)[2];
1270     udp_data[1] = ((unsigned char *)&from)[3];
1271     udp_data[2] = (net->udp_connections[con_id].
1272     inside_udp_port >> 8) & 0xff;
1273     udp_data[3] = net->udp_connections[con_id].
1274     inside_udp_port & 0xff;
1275     udp_data[4] = udp_len >> 8;
1276     udp_data[5] = udp_len & 0xff;
1277     udp_data[6] = 0;
1278     udp_data[7] = 0;
1279     memcpy(udp_data + 8, buf, res);
1280     /*
1281     * TODO: UDP checksum, if necessary. At least NetBSD
1282     * and OpenBSD accept UDP packets with 0x0000 in the
1283     * checksum field anyway.
1284     */
1285    
1286     while (bytes_converted < udp_len) {
1287     this_packets_data_length = udp_len - bytes_converted;
1288    
1289     /* Do we need to fragment? */
1290     if (this_packets_data_length > max_per_packet-34) {
1291     this_packets_data_length =
1292     max_per_packet - 34;
1293     while (this_packets_data_length & 7)
1294     this_packets_data_length --;
1295     }
1296    
1297     ip_len = 20 + this_packets_data_length;
1298    
1299     lp = net_allocate_ethernet_packet_link(net, extra,
1300     14 + 20 + this_packets_data_length);
1301    
1302     /* Ethernet header: */
1303     memcpy(lp->data + 0, net->udp_connections[con_id].
1304     ethernet_address, 6);
1305     memcpy(lp->data + 6, net->gateway_ethernet_addr, 6);
1306     lp->data[12] = 0x08; /* IP = 0x0800 */
1307     lp->data[13] = 0x00;
1308    
1309     /* IP header: */
1310     lp->data[14] = 0x45; /* ver */
1311     lp->data[15] = 0x00; /* tos */
1312     lp->data[16] = ip_len >> 8;
1313     lp->data[17] = ip_len & 0xff;
1314     lp->data[18] = net->udp_connections[con_id].udp_id >> 8;
1315     lp->data[19] = net->udp_connections[con_id].udp_id
1316     & 0xff;
1317     lp->data[20] = (fragment_ofs >> 8);
1318     if (bytes_converted + this_packets_data_length
1319     < udp_len)
1320     lp->data[20] |= 0x20; /* More fragments */
1321     lp->data[21] = fragment_ofs & 0xff;
1322     lp->data[22] = 0x40; /* ttl */
1323     lp->data[23] = 17; /* p = UDP */
1324     lp->data[26] = ((unsigned char *)&from)[4];
1325     lp->data[27] = ((unsigned char *)&from)[5];
1326     lp->data[28] = ((unsigned char *)&from)[6];
1327     lp->data[29] = ((unsigned char *)&from)[7];
1328     memcpy(lp->data + 30, net->udp_connections[con_id].
1329     inside_ip_address, 4);
1330     net_ip_checksum(lp->data + 14, 10, 20);
1331    
1332     memcpy(lp->data+34, udp_data + bytes_converted,
1333     this_packets_data_length);
1334    
1335     bytes_converted += this_packets_data_length;
1336     fragment_ofs = bytes_converted / 8;
1337    
1338     received_packets_this_tick ++;
1339     }
1340    
1341     /* This makes sure we check this connection AGAIN
1342     for more incoming UDP packets, before moving to the
1343     next connection: */
1344     con_id --;
1345     }
1346     }
1347    
1348    
1349     /*
1350     * net_tcp_rx_avail():
1351     *
1352     * Receive any available TCP packets (from the outside world).
1353     */
1354     void net_tcp_rx_avail(struct net *net, void *extra)
1355     {
1356     int received_packets_this_tick = 0;
1357     int max_packets_this_tick = 200;
1358     int con_id;
1359    
1360     for (con_id=0; con_id<MAX_TCP_CONNECTIONS; con_id++) {
1361     unsigned char buf[66000];
1362     ssize_t res, res2;
1363     fd_set rfds;
1364     struct timeval tv;
1365    
1366     if (received_packets_this_tick > max_packets_this_tick)
1367     break;
1368    
1369     if (!net->tcp_connections[con_id].in_use)
1370     continue;
1371    
1372     if (net->tcp_connections[con_id].socket < 0) {
1373     fatal("INTERNAL ERROR in net.c, tcp socket < 0"
1374     " but in use?\n");
1375     continue;
1376     }
1377    
1378     if (net->tcp_connections[con_id].incoming_buf == NULL) {
1379     net->tcp_connections[con_id].incoming_buf =
1380     malloc(TCP_INCOMING_BUF_LEN);
1381     if (net->tcp_connections[con_id].incoming_buf == NULL) {
1382     printf("out of memory allocating "
1383     "incoming_buf for con_id %i\n", con_id);
1384     exit(1);
1385     }
1386     }
1387    
1388     if (net->tcp_connections[con_id].state >=
1389     TCP_OUTSIDE_DISCONNECTED)
1390     continue;
1391    
1392     /* Is the socket available for output? */
1393     FD_ZERO(&rfds); /* write */
1394     FD_SET(net->tcp_connections[con_id].socket, &rfds);
1395     tv.tv_sec = tv.tv_usec = 0;
1396     errno = 0;
1397     res = select(net->tcp_connections[con_id].socket+1,
1398     NULL, &rfds, NULL, &tv);
1399    
1400     if (errno == ECONNREFUSED) {
1401     fatal("[ ECONNREFUSED: TODO ]\n");
1402     net->tcp_connections[con_id].state =
1403     TCP_OUTSIDE_DISCONNECTED;
1404     fatal("CHANGING TO TCP_OUTSIDE_DISCONNECTED "
1405     "(refused connection)\n");
1406     continue;
1407     }
1408    
1409     if (errno == ETIMEDOUT) {
1410     fatal("[ ETIMEDOUT: TODO ]\n");
1411     /* TODO */
1412     net->tcp_connections[con_id].state =
1413     TCP_OUTSIDE_DISCONNECTED;
1414     fatal("CHANGING TO TCP_OUTSIDE_DISCONNECTED "
1415     "(timeout)\n");
1416     continue;
1417     }
1418    
1419     if (net->tcp_connections[con_id].state ==
1420     TCP_OUTSIDE_TRYINGTOCONNECT && res > 0) {
1421     net->tcp_connections[con_id].state =
1422     TCP_OUTSIDE_CONNECTED;
1423     debug("CHANGING TO TCP_OUTSIDE_CONNECTED\n");
1424     net_ip_tcp_connectionreply(net, extra, con_id, 1,
1425     NULL, 0, 0);
1426     }
1427    
1428     if (net->tcp_connections[con_id].state ==
1429     TCP_OUTSIDE_CONNECTED && res < 1) {
1430     continue;
1431     }
1432    
1433     /*
1434     * Does this connection have unacknowledged data? Then, if
1435     * enough number of rounds have passed, try to resend it using
1436     * the old value of seqnr.
1437     */
1438     if (net->tcp_connections[con_id].incoming_buf_len != 0) {
1439     net->tcp_connections[con_id].incoming_buf_rounds ++;
1440     if (net->tcp_connections[con_id].incoming_buf_rounds >
1441     10000) {
1442     debug(" at seqnr %u but backing back to %u,"
1443     " resending %i bytes\n",
1444     net->tcp_connections[con_id].outside_seqnr,
1445     net->tcp_connections[con_id].
1446     incoming_buf_seqnr,
1447     net->tcp_connections[con_id].
1448     incoming_buf_len);
1449    
1450     net->tcp_connections[con_id].
1451     incoming_buf_rounds = 0;
1452     net->tcp_connections[con_id].outside_seqnr =
1453     net->tcp_connections[con_id].
1454     incoming_buf_seqnr;
1455    
1456     net_ip_tcp_connectionreply(net, extra, con_id,
1457     0, net->tcp_connections[con_id].
1458     incoming_buf,
1459     net->tcp_connections[con_id].
1460     incoming_buf_len, 0);
1461     }
1462     continue;
1463     }
1464    
1465     /* Don't receive unless the guest OS is ready! */
1466     if (((int32_t)net->tcp_connections[con_id].outside_seqnr -
1467     (int32_t)net->tcp_connections[con_id].inside_acknr) > 0) {
1468     /* fatal("YOYO 1! outside_seqnr - inside_acknr = %i\n",
1469     net->tcp_connections[con_id].outside_seqnr -
1470     net->tcp_connections[con_id].inside_acknr); */
1471     continue;
1472     }
1473    
1474     /* Is there incoming data available on the socket? */
1475     FD_ZERO(&rfds); /* read */
1476     FD_SET(net->tcp_connections[con_id].socket, &rfds);
1477     tv.tv_sec = tv.tv_usec = 0;
1478     res2 = select(net->tcp_connections[con_id].socket+1, &rfds,
1479     NULL, NULL, &tv);
1480    
1481     /* No more incoming TCP data on this connection? */
1482     if (res2 < 1)
1483     continue;
1484    
1485     res = read(net->tcp_connections[con_id].socket, buf, 1400);
1486     if (res > 0) {
1487     /* debug("\n -{- %lli -}-\n", (long long)res); */
1488     net->tcp_connections[con_id].incoming_buf_len = res;
1489     net->tcp_connections[con_id].incoming_buf_rounds = 0;
1490     net->tcp_connections[con_id].incoming_buf_seqnr =
1491     net->tcp_connections[con_id].outside_seqnr;
1492     debug(" putting %i bytes (seqnr %u) in the incoming "
1493     "buf\n", res, net->tcp_connections[con_id].
1494     incoming_buf_seqnr);
1495     memcpy(net->tcp_connections[con_id].incoming_buf,
1496     buf, res);
1497    
1498     net_ip_tcp_connectionreply(net, extra, con_id, 0,
1499     buf, res, 0);
1500     } else if (res == 0) {
1501     net->tcp_connections[con_id].state =
1502     TCP_OUTSIDE_DISCONNECTED;
1503     debug("CHANGING TO TCP_OUTSIDE_DISCONNECTED, read"
1504     " res=0\n");
1505     net_ip_tcp_connectionreply(net, extra, con_id, 0,
1506     NULL, 0, 0);
1507     } else {
1508     net->tcp_connections[con_id].state =
1509     TCP_OUTSIDE_DISCONNECTED;
1510     fatal("CHANGING TO TCP_OUTSIDE_DISCONNECTED, "
1511     "read res<=0, errno = %i\n", errno);
1512     net_ip_tcp_connectionreply(net, extra, con_id, 0,
1513     NULL, 0, 0);
1514     }
1515    
1516     net->timestamp ++;
1517     net->tcp_connections[con_id].last_used_timestamp =
1518     net->timestamp;
1519     }
1520     }
1521    
1522    

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