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[openwrt/svn-archive/archive.git] / package / siit / src / siit.c
1 /*
2 * siit.c: the Stateless IP/ICMP Translator (SIIT) module for Linux.
3 *
4 *
5 */
6
7 #include <linux/version.h>
8 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,33))
9 #include <generated/autoconf.h>
10 #else
11 #include <linux/autoconf.h>
12 #endif
13 #include <linux/module.h>
14 #include <linux/sched.h>
15 #include <linux/kernel.h> /* printk() */
16 #include <linux/slab.h>
17
18 #include <linux/errno.h> /* error codes */
19 #include <linux/types.h> /* size_t */
20 #include <linux/interrupt.h> /* mark_bh */
21 #include <linux/random.h>
22 #include <linux/in.h>
23 #include <linux/netdevice.h> /* struct device, and other headers */
24 #include <linux/etherdevice.h> /* eth_type_trans */
25 #include <net/ip.h> /* struct iphdr */
26 #include <net/icmp.h> /* struct icmphdr */
27 #include <net/ipv6.h>
28 #include <net/udp.h>
29 #include <linux/skbuff.h>
30 #include <linux/in6.h>
31 #include <linux/init.h>
32 #include <asm/uaccess.h>
33 #include <asm/checksum.h>
34 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0)
35 #include <net/ip6_checksum.h>
36 #endif
37 #include <linux/in6.h>
38 #include "siit.h"
39
40 MODULE_AUTHOR("Dmitriy Moscalev, Grigory Klyuchnikov, Felix Fietkau");
41
42 /*
43 * If tos_ignore_flag != 0, we don't copy TOS and Traffic Class
44 * from origin paket and set it to 0
45 */
46 int tos_ignore_flag = 0;
47
48 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
49 static inline void
50 skb_reset_mac_header(struct sk_buff *skb)
51 {
52 skb->mac.raw=skb->data;
53 }
54
55 static struct net_device_stats *
56 siit_get_stats(struct net_device *dev)
57 {
58 return netdev_priv(dev);
59 }
60
61 static inline void random_ether_addr(u8 *addr)
62 {
63 get_random_bytes (addr, ETH_ALEN);
64 addr [0] &= 0xfe; /* clear multicast bit */
65 addr [0] |= 0x02; /* set local assignment bit (IEEE802) */
66 }
67
68
69 #define siit_stats(_dev) ((struct net_device_stats *)netdev_priv(_dev))
70 #else
71 #define siit_stats(_dev) (&(_dev)->stats)
72 #endif
73
74 /*
75 * The Utility stuff
76 */
77
78 #ifdef SIIT_DEBUG
79 /* print dump bytes (data point data area sizeof len and message
80 * before dump.
81 */
82 static int siit_print_dump(char *data, int len, char *message)
83 {
84 int i;
85 int j = 0, k = 1;
86
87 len = len > BUFF_SIZE ? BUFF_SIZE : len;
88 printk("%s:\n", message);
89 for (i=0; i < len; i++, k++) {
90 if( i == len-1 || k == 16) {
91 printk("%02x\n", (~(~0 << 8) & *(data+i)));
92 j = 0;
93 k = 0;
94 }
95 else if (j) {
96 printk("%02x ", (~(~0 << 8) & *(data+i)));
97 j--;
98 }
99 else {
100 printk("%02x", (~(~0 << 8) & *(data+i)));
101 j++;
102 }
103 }
104 return 0;
105 }
106 #endif
107
108 /*
109 * Open and close
110 */
111 static int siit_open(struct net_device *dev)
112 {
113 netif_start_queue(dev);
114 return 0;
115 }
116
117
118 static int siit_release(struct net_device *dev)
119 {
120 netif_stop_queue(dev); /* can't transmit any more */
121 return 0;
122 }
123
124 /*
125 * Translation IPv4 to IPv6 stuff
126 *
127 * ip4_ip6 (src, len, dst, include_flag)
128 *
129 * where
130 * src - buffer with original IPv4 packet,
131 * len - size of original packet,
132 * dst - new buffer for IPv6 packet,
133 * include_flag - if = 1, dst point to IPv4 packet that is ICMP error
134 * included IP packet, else = 0
135 */
136
137 static int ip4_ip6(char *src, int len, char *dst, int include_flag)
138 {
139 struct iphdr *ih4 = (struct iphdr *) src; /* point to current IPv4 header struct */
140 struct icmphdr *icmp_hdr; /* point to current ICMPv4 header struct */
141 struct udphdr *udp_hdr; /* point to current IPv4 UDP header struct */
142
143 struct ipv6hdr *ih6 = (struct ipv6hdr *) dst; /* point to current IPv6 header struct */
144 struct frag_hdr *ih6_frag = (struct frag_hdr *)(dst+sizeof(struct ipv6hdr));
145 /* point to current IPv6 fragment header struct */
146 struct icmp6hdr *icmp6_hdr; /* point to current ICMPv6 header */
147
148 int hdr_len = (int)(ih4->ihl * 4); /* IPv4 header length */
149 int icmp_len; /* ICMPv4 packet length */
150 int plen; /* payload length */
151
152 unsigned int csum; /* need to calculate ICMPv6 and UDP checksum */
153 int fl_csum = 0; /* flag to calculate UDP checksum */
154 int icmperr = 1; /* flag to indicate ICMP error message and to need
155 translate ICMP included IP packet */
156 int fr_flag = 0; /* fragment flag, if = 0 - don't add
157 fragment header */
158 __u16 new_tot_len; /* need to calculate IPv6 total length */
159 __u8 new_nexthdr; /* next header code */
160 __u16 icmp_ptr = 0; /* Pointer field in ICMP_PARAMETERPROB */
161
162 #ifdef SIIT_DEBUG /* print IPv4 header dump */
163 siit_print_dump(src, hdr_len, "siit: ip4_ip6() (in) ip4 header dump");
164 #endif
165
166 /* If DF == 1 && MF == 0 && Fragment Offset == 0
167 * or this packet is ICMP included IP packet
168 * we don't need fragment header */
169 if (ntohs(ih4->frag_off) == IP_DF || include_flag ) {
170 /* not fragment and we need not to add Fragment
171 * Header to IPv6 packet. */
172 /* total length = total length from IPv4 packet */
173 new_tot_len = ntohs(ih4->tot_len);
174
175 if (ih4->protocol == IPPROTO_ICMP)
176 new_nexthdr = NEXTHDR_ICMP;
177 else
178 new_nexthdr = ih4->protocol;
179 }
180 else {
181 /* need to add Fragment Header */
182 fr_flag = 1;
183 /* total length = total length from IPv4 packet +
184 length of Fragment Header */
185 new_tot_len = ntohs(ih4->tot_len) + sizeof(struct frag_hdr);
186 /* IPv6 Header NextHeader = NEXTHDR_FRAGMENT */
187 new_nexthdr = NEXTHDR_FRAGMENT;
188 /* Fragment Header NextHeader copy from IPv4 packet */
189 if (ih4->protocol == IPPROTO_ICMP)
190 ih6_frag->nexthdr = NEXTHDR_ICMP;
191 else
192 ih6_frag->nexthdr = ih4->protocol;
193
194 /* copy frag offset from IPv4 packet */
195 ih6_frag->frag_off = htons((ntohs(ih4->frag_off) & IP_OFFSET) << 3);
196 /* copy MF flag from IPv4 packet */
197 ih6_frag->frag_off = htons((ntohs(ih6_frag->frag_off) |
198 ((ntohs(ih4->frag_off) & IP_MF) >> 13)));
199 /* copy Identification field from IPv4 packet */
200 ih6_frag->identification = htonl(ntohs(ih4->id));
201 /* reserved field initialized to zero */
202 ih6_frag->reserved = 0;
203 }
204
205 /* Form rest IPv6 fields */
206
207 /*
208 * At this point we need to add checking of unxpired source
209 * route optin and if it is, send ICMPv4 "destination
210 * unreacheble/source route failes" Type 3/Code 5 and
211 * drop packet. (NOT RELEASED YET)
212 */
213
214 /* IP version = 6 */
215 ih6->version = 6;
216
217 if (tos_ignore_flag) {
218 ih6->priority = 0;
219 ih6->flow_lbl[0] = 0;
220 } else {
221 ih6->priority = (ih4->tos & 0xf0) >> 4;
222 ih6->flow_lbl[0] = (ih4->tos & 0x0f) << 4;
223 }
224 ih6->flow_lbl[1] = 0;
225 ih6->flow_lbl[2] = 0;
226
227 /* Hop Limit = IPv4 TTL */
228 ih6->hop_limit = ih4->ttl;
229
230 /* Translate source destination addresses,
231 for IPv6 host it's IPv4-translated IPv6 address,
232 for IPv4 host it's IPv4-mapped IPv6 address
233
234 !!WARNING!! Instead IPv4-mapped IPv6 addresses we use addreesses
235 with unused prefix ::ffff:ffff:0:0/96, because KAME implementation
236 doesn't support IPv4-mapped addresses in IPv6 packets and discard them.
237
238 */
239
240 if (include_flag) {
241 /*
242 It's ICMP included IP packet and there is a diffirence
243 in src/dst addresses then src/dst in normal direction
244 */
245
246 /*
247 Source address
248 is IPv4-translated IPv6 address because packet traveled
249 from IPv6 to IPv4 area
250 */
251 ih6->saddr.in6_u.u6_addr32[0] = 0;
252 ih6->saddr.in6_u.u6_addr32[1] = 0;
253 ih6->saddr.in6_u.u6_addr32[2] = htonl(TRANSLATED_PREFIX); /* to network order bytes */
254 ih6->saddr.in6_u.u6_addr32[3] = ih4->saddr;
255
256 /*
257 Destination address
258 is IPv4-mapped address (but it's not IPv4- mapped, we use
259 prefix ::ffff:ffff:0:0/96
260 */
261 ih6->daddr.in6_u.u6_addr32[0] = 0;
262 ih6->daddr.in6_u.u6_addr32[1] = 0;
263 ih6->daddr.in6_u.u6_addr32[2] = htonl(MAPPED_PREFIX); /* to network order bytes */
264 ih6->daddr.in6_u.u6_addr32[3] = ih4->daddr;
265 }
266 else {
267
268 /*
269 This is normal case (packet isn't included IP packet)
270
271 Source address
272 is IPv4-mapped address (but it's not IPv4- mapped, we use
273 prefix ::ffff:ffff:0:0/96)
274 */
275 ih6->saddr.in6_u.u6_addr32[0] = 0;
276 ih6->saddr.in6_u.u6_addr32[1] = 0;
277 ih6->saddr.in6_u.u6_addr32[2] = htonl(MAPPED_PREFIX); /* to network order bytes */
278 ih6->saddr.in6_u.u6_addr32[3] = ih4->saddr;
279
280 /* Destination address
281 is is IPv4-translated IPv6 address
282 */
283 ih6->daddr.in6_u.u6_addr32[0] = 0;
284 ih6->daddr.in6_u.u6_addr32[1] = 0;
285 ih6->daddr.in6_u.u6_addr32[2] = htonl(TRANSLATED_PREFIX); /* to network order bytes */
286 ih6->daddr.in6_u.u6_addr32[3] = ih4->daddr;
287 }
288
289 /* Payload Length */
290 plen = new_tot_len - hdr_len; /* Payload length = IPv4 total len - IPv4 header len */
291 ih6->payload_len = htons(plen);
292
293 /* Next Header */
294 ih6->nexthdr = new_nexthdr; /* Next Header */
295
296 /* Process ICMP protocols data */
297
298 switch (ih4->protocol) {
299 case IPPROTO_ICMP:
300 if ( (ntohs(ih4->frag_off) & IP_OFFSET) != 0 || (ntohs(ih4->frag_off) & IP_MF) != 0 ) {
301 PDEBUG("ip4_ip6(): don't translate ICMPv4 fragments - packet dropped.\n");
302 return -1;
303 }
304
305 icmp_hdr = (struct icmphdr *) (src+hdr_len); /* point to ICMPv4 header */
306 csum = 0;
307 icmp_len = ntohs(ih4->tot_len) - hdr_len; /* ICMPv4 packet length */
308 icmp6_hdr = (struct icmp6hdr *)(dst+sizeof(struct ipv6hdr)
309 +fr_flag*sizeof(struct frag_hdr)); /* point to ICMPv6 header */
310
311 if (include_flag) {
312 /* ICMPv4 packet cannot be included in ICMPv4 Error message */
313 /* !!! May be it's WRONG !!! ICMPv4 QUERY packet can be included
314 in ICMPv4 Error message */
315 PDEBUG("ip4_ip6(): It's included ICMPv4 in ICMPv4 Error message - packet dropped.\n");
316 return -1;
317 }
318
319 /* Check ICMPv4 Type field */
320 switch (icmp_hdr->type) {
321 /* ICMP Error messages */
322 /* Destination Unreachable (Type 3) */
323 case ICMP_DEST_UNREACH:
324 icmp6_hdr->icmp6_type = ICMPV6_DEST_UNREACH; /* to Type 1 */
325 icmp6_hdr->icmp6_unused = 0;
326 switch (icmp_hdr->code)
327 {
328 case ICMP_NET_UNREACH: /* Code 0 */
329 case ICMP_HOST_UNREACH: /* Code 1 */
330 case ICMP_SR_FAILED: /* Code 5 */
331 case ICMP_NET_UNKNOWN: /* Code 6 */
332 case ICMP_HOST_UNKNOWN: /* Code 7 */
333 case ICMP_HOST_ISOLATED: /* Code 8 */
334 case ICMP_NET_UNR_TOS: /* Code 11 */
335 case ICMP_HOST_UNR_TOS: /* Code 12 */
336 icmp6_hdr->icmp6_code = ICMPV6_NOROUTE; /* to Code 0 */
337 break;
338 case ICMP_PROT_UNREACH: /* Code 2 */
339 icmp6_hdr->icmp6_type = ICMPV6_PARAMPROB; /* to Type 4 */
340 icmp6_hdr->icmp6_code = ICMPV6_UNK_NEXTHDR; /* to Code 1 */
341 /* Set pointer filed to 6, it's octet offset IPv6 Next Header field */
342 icmp6_hdr->icmp6_pointer = htonl(6);
343 break;
344 case ICMP_PORT_UNREACH: /* Code 3 */
345 icmp6_hdr->icmp6_code = ICMPV6_PORT_UNREACH; /* to Code 4 */
346 break;
347 case ICMP_FRAG_NEEDED: /* Code 4 */
348 icmp6_hdr->icmp6_type = ICMPV6_PKT_TOOBIG; /* to Type 2 */
349 icmp6_hdr->icmp6_code = 0;
350 /* Correct MTU */
351 if (icmp_hdr->un.frag.mtu == 0)
352 /* we use minimum MTU for IPv4 PMTUv4 RFC1191, section 5;
353 IPv6 implementation wouldn't accept Path MTU < 1280,
354 but it records info correctly to always include
355 a fragment header */
356 icmp6_hdr->icmp6_mtu = htonl(576);
357 else
358 /* needs to adjusted for difference between IPv4/IPv6 headers
359 * SIIT RFC2765, section 3.3,
360 * we assume that difference is 20 bytes */
361 icmp6_hdr->icmp6_mtu = htonl(ntohs(icmp_hdr->un.frag.mtu)+IP4_IP6_HDR_DIFF);
362
363 break;
364 case ICMP_NET_ANO: /* Code 9 */
365 case ICMP_HOST_ANO: /* Code 10 */
366 icmp6_hdr->icmp6_code = ICMPV6_ADM_PROHIBITED; /* to Code 1 */
367 break;
368 default: /* discard any other Code */
369 PDEBUG("ip4_ip6(): Unknown ICMPv4 Type %d Code %d - packet dropped.\n",
370 ICMP_DEST_UNREACH, icmp_hdr->code);
371 return -1;
372 }
373 break;
374 /* Time Exceeded (Type 11) */
375 case ICMP_TIME_EXCEEDED:
376 icmp6_hdr->icmp6_type = ICMPV6_TIME_EXCEED;
377 icmp6_hdr->icmp6_code = icmp_hdr->code;
378 break;
379 /* Parameter Problem (Type 12) */
380 case ICMP_PARAMETERPROB:
381 icmp6_hdr->icmp6_type = ICMPV6_PARAMPROB;
382 icmp6_hdr->icmp6_code = icmp_hdr->code;
383
384 icmp_ptr = ntohs(icmp_hdr->un.echo.id) >> 8;
385 switch (icmp_ptr) {
386 case 0:
387 icmp6_hdr->icmp6_pointer = 0; /* IPv4 Version -> IPv6 Version */
388 break;
389 case 2:
390 icmp6_hdr->icmp6_pointer = __constant_htonl(4); /* IPv4 length -> IPv6 Payload Length */
391 break;
392 case 8:
393 icmp6_hdr->icmp6_pointer = __constant_htonl(7); /* IPv4 TTL -> IPv6 Hop Limit */
394 break;
395 case 9:
396 icmp6_hdr->icmp6_pointer = __constant_htonl(6); /* IPv4 Protocol -> IPv6 Next Header */
397 break;
398 case 12:
399 icmp6_hdr->icmp6_pointer = __constant_htonl(8); /* IPv4 Src Addr -> IPv6 Src Addr */
400 break;
401 case 16:
402 icmp6_hdr->icmp6_pointer = __constant_htonl(24); /* IPv4 Dst Addr -> IPv6 Dst Addr */
403 break;
404 default:
405 icmp6_hdr->icmp6_pointer = 0xffffffff; /* set to all ones in any other cases */
406 break;
407 }
408 break;
409 case ICMP_ECHO:
410 icmperr = 0;
411 icmp6_hdr->icmp6_type = ICMPV6_ECHO_REQUEST;
412 icmp6_hdr->icmp6_code = 0;
413 /* Copy rest ICMP data to new IPv6 packet without changing */
414 memcpy(((char *)icmp6_hdr)+4, ((char *)icmp_hdr)+4, len - hdr_len - 4);
415 break;
416
417 case ICMP_ECHOREPLY:
418 icmperr = 0;
419 icmp6_hdr->icmp6_type = ICMPV6_ECHO_REPLY;
420 icmp6_hdr->icmp6_code = 0;
421 /* Copy rest ICMP data to new IPv6 packet without changing */
422 memcpy(((char *)icmp6_hdr)+4, ((char *)icmp_hdr)+4, len - hdr_len - 4);
423 break;
424
425 /* Discard any other ICMP messages */
426 default:
427 PDEBUG("ip4_ip6(): Unknown ICMPv4 packet Type %x - packet dropped.\n", icmp_hdr->type);
428 return -1;
429 }
430
431 /* Now if it's ICMPv4 Error message we must translate included IP packet */
432
433 if (icmperr) {
434 /* Call our ip4_ip6() to translate included IP packet */
435 if (ip4_ip6(src+hdr_len+sizeof(struct icmphdr), len - hdr_len - sizeof(struct icmphdr),
436 dst+sizeof(struct ipv6hdr)+fr_flag*sizeof(struct frag_hdr)
437 +sizeof(struct icmp6hdr), 1) == -1) {
438 PDEBUG("ip4_ip6(): Uncorrect translation of ICMPv4 Error message - packet dropped.\n");
439 return -1;
440 }
441 /* correct ICMPv6 packet length for diffirence between IPv4 and IPv6 headers
442 in included IP packet
443 */
444 icmp_len += 20;
445 /* and correct Payload length for diffirence between IPv4 and IPv6 headers */
446 plen += 20;
447 ih6->payload_len = htons(plen);
448 }
449
450 /* Calculate ICMPv6 checksum */
451
452 icmp6_hdr->icmp6_cksum = 0;
453 csum = 0;
454
455 csum = csum_partial((u_char *)icmp6_hdr, icmp_len, csum);
456 icmp6_hdr->icmp6_cksum = csum_ipv6_magic(&ih6->saddr, &ih6->daddr, icmp_len,
457 IPPROTO_ICMPV6, csum);
458 break;
459
460 /* Process TCP protocols data */
461 case IPPROTO_TCP:
462 /* Copy TCP data to new IPv6 packet without changing */
463 memcpy(dst+sizeof(struct ipv6hdr)+fr_flag*sizeof(struct frag_hdr),
464 src+hdr_len, len - hdr_len);
465 break;
466
467 /* Process UDP protocols data */
468 case IPPROTO_UDP:
469 udp_hdr = (struct udphdr *)(src+hdr_len);
470 if ((ntohs(ih4->frag_off) & IP_OFFSET) == 0) {
471 if ((ntohs(ih4->frag_off) & IP_MF) != 0) {
472 /* It's a first fragment */
473 if (udp_hdr->check == 0) {
474 /* System management event */
475 printk("siit: First fragment of UDP with zero checksum - packet droped\n");
476 printk("siit: addr: %x src port: %d dst port: %d\n",
477 htonl(ih4->saddr), htons(udp_hdr->source), htons(udp_hdr->dest));
478 return -1;
479 }
480 }
481 else if (udp_hdr->check == 0)
482 fl_csum = 1;
483 }
484
485 /* Copy UDP data to new IPv6 packet */
486 udp_hdr = (struct udphdr *)(dst+sizeof(struct ipv6hdr)
487 + fr_flag*sizeof(struct frag_hdr));
488 memcpy((char *)udp_hdr, src+hdr_len, len - hdr_len);
489
490 /* Calculate UDP checksum if UDP checksum in IPv4 packet was ZERO
491 and if it isn't included IP packet
492 */
493 if (fl_csum && (!include_flag)) {
494 udp_hdr->check = 0;
495 csum = 0;
496 csum = csum_partial((unsigned char *)udp_hdr, plen - fr_flag*sizeof(struct frag_hdr), csum);
497 udp_hdr->check = csum_ipv6_magic(&ih6->saddr, &ih6->daddr, plen -
498 fr_flag*sizeof(struct frag_hdr), IPPROTO_UDP, csum);
499 }
500 break;
501
502 /* Discard packets with any other protocol */
503 default:
504 PDEBUG("ip4_ip6(): Unknown upper protocol - packet dropped.\n");
505 return -1;
506 }
507
508 #ifdef SIIT_DEBUG
509 siit_print_dump(dst, sizeof(struct ipv6hdr), "siit: ip4_ip6(): (out) ipv6 header dump");
510 #endif
511
512 return 0;
513 }
514
515 /*
516 * Translation IPv6 to IPv4 stuff
517 *
518 * ip6_ip4(src, len, dst, include_flag)
519 *
520 * where
521 * src - buffer with original IPv6 packet,
522 * len - size of original packet,
523 * dst - new buffer for IPv4 packet,
524 * include_flag - if = 1, dst point to IPv6 packet that is ICMP error
525 * included IP packet, else = 0
526 *
527 */
528
529 static int ip6_ip4(char *src, int len, char *dst, int include_flag)
530 {
531 struct ipv6hdr *ip6_hdr; /* point to current IPv6 header struct */
532 struct iphdr *ip_hdr; /* point to current IPv4 header struct */
533 int opts_len = 0; /* to sum Option Headers length */
534 int icmperr = 1; /* if = 1, indicate that packet is ICMP Error message, else = 0 */
535 int ntot_len = 0; /* to calculate IPv6 Total Length field */
536 int real_len;
537 int len_delta;
538 int ip6_payload_len;
539 int inc_opts_len = 0; /* to sum Option Headers length in ICMP included IP packet */
540 __u8 next_hdr; /* Next Header */
541
542 #ifdef SIIT_DEBUG
543 siit_print_dump(src, sizeof(struct ipv6hdr), "siit: ip6_ip4(): (in) ipv6 header dump");
544 #endif
545
546 if ( (len_delta = len - sizeof(struct ipv6hdr)) >= 0)
547 {
548 ip6_hdr = (struct ipv6hdr *)src;
549 ip_hdr = (struct iphdr *)dst;
550
551 real_len = sizeof(struct iphdr);
552
553 /* Check validation of Saddr & Daddr? is a packet to fall under our translation? */
554 if (include_flag) { /* It's ICMP included IP packet,
555 about process include_flag see comment in ip4_ip6() */
556 if (ip6_hdr->saddr.s6_addr32[2] != htonl(MAPPED_PREFIX)) {
557 PDEBUG("ip6_ip4(): Included IP packet Src addr isn't mapped addr: %x%x%x%x, packet dropped.\n",
558 ip6_hdr->saddr.s6_addr32[0], ip6_hdr->saddr.s6_addr32[1],
559 ip6_hdr->saddr.s6_addr32[2], ip6_hdr->saddr.s6_addr32[3]);
560 return -1;
561 }
562 if ( ip6_hdr->daddr.s6_addr32[2] != htonl(TRANSLATED_PREFIX)) {
563 PDEBUG("ip6_ip4(): Included IP packet Dst addr isn't translated addr: %x%x%x%x, packet dropped.\n",
564 ip6_hdr->daddr.s6_addr32[0], ip6_hdr->daddr.s6_addr32[1],
565 ip6_hdr->daddr.s6_addr32[2], ip6_hdr->daddr.s6_addr32[3]);
566 return -1;
567 }
568 }
569 else { /* It's normal IP packet (not included in ICMP) */
570 if (ip6_hdr->saddr.s6_addr32[2] != htonl(TRANSLATED_PREFIX)) {
571 PDEBUG("ip6_ip4(): Src addr isn't translated addr: %x%x%x%x, packet dropped.\n",
572 ip6_hdr->saddr.s6_addr32[0], ip6_hdr->saddr.s6_addr32[1],
573 ip6_hdr->saddr.s6_addr32[2], ip6_hdr->saddr.s6_addr32[3]);
574 return -1;
575 }
576 if ( ip6_hdr->daddr.s6_addr32[2] != htonl(MAPPED_PREFIX)) {
577 PDEBUG("ip6_ip4(): Dst addr isn't mapped addr: %x%x%x%x, packet dropped.\n",
578 ip6_hdr->daddr.s6_addr32[0], ip6_hdr->daddr.s6_addr32[1],
579 ip6_hdr->daddr.s6_addr32[2], ip6_hdr->daddr.s6_addr32[3]);
580 return -1;
581 }
582 }
583
584 /* Set IPv4 Fragment Offset and ID to 0
585 before process any Option Headers */
586 ip_hdr->frag_off = 0;
587 ip_hdr->id = 0;
588
589 /*
590 * We process only Fragment Header. Any other options headers
591 * are ignored, i.e. there is no attempt to translate them.
592 * However, the Total Length field and the Protocol field would
593 * have to be adjusted to "skip" these extension headers.
594 */
595
596 next_hdr = ip6_hdr->nexthdr;
597
598 /* Hop_by_Hop options header (ip6_hdr->nexthdr = 0). It must
599 * appear only in IPv6 header's Next Header field.
600 */
601 if (next_hdr == NEXTHDR_HOP) {
602 if ( (len_delta - sizeof(struct ipv6_opt_hdr)) >= 0)
603 {
604 struct ipv6_opt_hdr *ip6h =
605 (struct ipv6_opt_hdr *)(src+sizeof(struct ipv6hdr) + opts_len);
606 if ( (len_delta -= ip6h->hdrlen*8 + 8) >= 0)
607 {
608 opts_len += ip6h->hdrlen*8 + 8; /* See RFC 2460 page 11:
609 Hdr Ext Len 8-bit unsigned integer. Length of the Hop-by-
610 Hop Options header in 8-octet units, not
611 including the first 8 octets.
612 */
613 next_hdr = ip6h->nexthdr;
614 }
615 else
616 {
617 PDEBUG("ip6_ip4(): hop_by_hop header error, packet droped");
618 /* Generate ICMP Parameter Problem */
619 return -1;
620 }
621 }
622 }
623
624 if (len_delta > 0)
625 {
626 while(next_hdr != NEXTHDR_ICMP && next_hdr != NEXTHDR_TCP
627 && next_hdr != NEXTHDR_UDP)
628 {
629 /* Destination options header */
630 if (next_hdr == NEXTHDR_DEST)
631 {
632 if ( (len_delta - sizeof(struct ipv6_opt_hdr)) >= 0)
633 {
634 struct ipv6_opt_hdr *ip6d =
635 (struct ipv6_opt_hdr *)(src + sizeof(struct ipv6hdr) + opts_len);
636 if ( (len_delta -= ip6d->hdrlen*8 + 8) >= 0)
637 {
638 opts_len += ip6d->hdrlen*8 + 8;
639 next_hdr = ip6d->nexthdr;
640 }
641 }
642 else
643 {
644 PDEBUG("ip6_ip4(): destination header error, packet droped");
645 /* Generate ICMP Parameter Problem */
646 return -1;
647 }
648 }
649 /* Routing options header */
650 else if (next_hdr == NEXTHDR_ROUTING)
651 {
652 if ( (len_delta - sizeof(struct ipv6_rt_hdr)) >= 0)
653 {
654 struct ipv6_rt_hdr *ip6rt =
655 (struct ipv6_rt_hdr *)(src+sizeof(struct ipv6hdr) + opts_len);
656 /* RFC 2765 SIIT, 4.1:
657 If a routing header with a non-zero Segments Left field is present
658 then the packet MUST NOT be translated, and an ICMPv6 "parameter
659 problem/ erroneous header field encountered" (Type 4/Code 0) error
660 message, with the Pointer field indicating the first byte of the
661 Segments Left field, SHOULD be returned to the sender.
662 */
663 if (ip6rt->segments_left != 0) {
664 /* Build ICMPv6 "Parameter Problem/Erroneous Header
665 Field Encountered" & drop the packet */
666 /* !!! We don't send ICMPv6 "Parameter Problem" !!! */
667 PDEBUG("ip6_ip4(): routing header type != 0\n");
668 return -1;
669 }
670 if ( (len_delta -= ip6rt->hdrlen*8 + 8) >= 0)
671 {
672 opts_len += ip6rt->hdrlen*8 + 8;
673 next_hdr = ip6rt->nexthdr;
674 }
675 else
676 {
677 PDEBUG("ip6_ip4(): routing header error, packet droped");
678 /* Generate ICMP Parameter Problem */
679 return -1;
680 }
681 }
682 }
683 /* Fragment options header */
684 else if (next_hdr == NEXTHDR_FRAGMENT)
685 {
686 if ( (len_delta -= sizeof(struct frag_hdr)) >= 0)
687 {
688 struct frag_hdr *ip6f =
689 (struct frag_hdr *)(src+sizeof(struct ipv6hdr)+opts_len);
690
691 opts_len += sizeof(struct frag_hdr); /* Frag Header Length = 8 */
692 ip_hdr->id = htons(ntohl(ip6f->identification)); /* ID field */
693 ip_hdr->frag_off = htons((ntohs(ip6f->frag_off) & IP6F_OFF_MASK) >> 3);
694 /* fragment offset */
695 ip_hdr->frag_off = htons(ntohs(ip_hdr->frag_off) |
696 ((ntohs(ip6f->frag_off) & IP6F_MORE_FRAG) << 13));
697 /* more fragments flag */
698 next_hdr = ip6f->nexthdr;
699 }
700 else
701 {
702 PDEBUG("ip6_ip4(): fragment header error, packet droped");
703 /* Generate ICMP Parameter Problem */
704 return -1;
705 }
706 }
707 /* No Next Header */
708 else if (next_hdr == NEXTHDR_NONE)
709 {
710 /* RFC 2460 IPv6 Specification, 4.7
711 4.7 No Next Header
712
713 The value 59 in the Next Header field of an IPv6 header or any
714 extension header indicates that there is nothing following that
715 header. If the Payload Length field of the IPv6 header indicates the
716 presence of octets past the end of a header whose Next Header field
717 contains 59, those octets must be ignored, and passed on unchanged if
718 the packet is forwarded.
719 */
720 break;
721 }
722 else if (next_hdr == NEXTHDR_ESP || next_hdr == NEXTHDR_AUTH)
723 {
724 PDEBUG("ip6_ip4(): cannot translate AUTH or ESP extention header, packet dropped\n");
725 return -1;
726 }
727 else if (next_hdr == NEXTHDR_IPV6)
728 {
729 PDEBUG("ip6_ip4(): cannot translate IPv6-IPv6 packet, packet dropped\n");
730 return -1;
731 }
732 else if (next_hdr == 0)
733 {
734 /* As say RFC 2460 (IPv6 Spec) we should discard the packet and send an
735 ICMP Parameter Problem message to the source of the packet, with an
736 ICMP Code value of 1 ("unrecognized Next Header type encountered")
737 and the ICMP Pointer field containing the offset of the unrecognized
738 value within the original packet
739 */
740 /* NOT IMPLEMENTED */
741 PDEBUG("ip6_ip4(): NEXTHDR in extention header = 0, packet dropped\n");
742 return -1;
743 }
744 else
745 {
746 PDEBUG("ip6_ip4(): cannot translate extention header = %d, packet dropped\n", next_hdr);
747 return -1;
748 }
749 }
750 }
751 }
752 else
753 {
754 PDEBUG("ip6_ip4(): error packet len, packet dropped.\n");
755 return -1;
756 }
757
758 /* Building ipv4 packet */
759
760 ip_hdr->version = IPVERSION;
761 ip_hdr->ihl = 5;
762
763 /* TOS see comment about TOS in ip4_ip6() */
764 if (tos_ignore_flag)
765 ip_hdr->tos = 0;
766 else {
767 ip_hdr->tos = ip6_hdr->priority << 4;
768 ip_hdr->tos = ip_hdr->tos | (ip6_hdr->flow_lbl[0] >> 4);
769 }
770
771 /* IPv4 Total Len = IPv6 Payload Len +
772 IPv4 Header Len (without options) - Options Headers Len */
773 ip6_payload_len = ntohs(ip6_hdr->payload_len);
774
775 if (ip6_payload_len == 0)
776 ntot_len = 0;
777 else
778 ntot_len = ip6_payload_len + IP4_IP6_HDR_DIFF - opts_len;
779
780 ip_hdr->tot_len = htons(ntot_len);
781
782 /* IPv4 TTL = IPv6 Hop Limit */
783 ip_hdr->ttl = ip6_hdr->hop_limit;
784
785 /* IPv4 Protocol = Next Header that will point to upper layer protocol */
786 ip_hdr->protocol = next_hdr;
787
788 /* IPv4 Src addr = last 4 bytes from IPv6 Src addr */
789 ip_hdr->saddr = ip6_hdr->saddr.s6_addr32[3];
790 /* IPv4 Dst addr = last 4 bytes from IPv6 Dst addr */
791 ip_hdr->daddr = ip6_hdr->daddr.s6_addr32[3];
792
793 /* Calculate IPv4 header checksum */
794 ip_hdr->check = 0;
795 ip_hdr->check = ip_fast_csum((unsigned char *)ip_hdr, ip_hdr->ihl);
796
797 if (len_delta > 0)
798 {
799 /* PROCESS ICMP */
800
801 if (next_hdr == NEXTHDR_ICMP)
802 {
803 struct icmp6hdr *icmp6_hdr;
804 struct icmphdr *icmp_hdr;
805
806 if ((len_delta -= sizeof(struct icmp6hdr)) >= 0)
807 {
808 icmp6_hdr = (struct icmp6hdr *)(src + sizeof(struct ipv6hdr) + opts_len);
809 icmp_hdr = (struct icmphdr *)(dst + sizeof(struct iphdr));
810
811 real_len += len_delta + sizeof(struct icmphdr);
812
813 /* There is diffirent between ICMPv4/ICMPv6 protocol codes
814 IPPROTO_ICMP = 1
815 IPPROTO_ICMPV6 = 58 */
816 ip_hdr->protocol = IPPROTO_ICMP;
817
818 if (include_flag) {
819 /* !!! Warnig !!! We discard ICMP packets with any ICMP as included
820 in ICMP Error. But ICMP Error messages can include ICMP Query message
821 */
822 if (icmp6_hdr->icmp6_type != ICMPV6_ECHO_REQUEST)
823 {
824 PDEBUG("ip6_ip4(): included ICMPv6 in ICMPv6 Error message, packet dropped\n");
825 return -1;
826 }
827 }
828
829 /* Translate ICMPv6 to ICMPv4 */
830 switch (icmp6_hdr->icmp6_type)
831 {
832 /* ICMP Error messages */
833 /* Destination Unreachable (Type 1) */
834 case ICMPV6_DEST_UNREACH: /* Type 1 */
835 icmp_hdr->type = ICMP_DEST_UNREACH; /* to Type 3 */
836 icmp_hdr->un.echo.id = 0;
837 icmp_hdr->un.echo.sequence = 0;
838 switch (icmp6_hdr->icmp6_code)
839 {
840 case ICMPV6_NOROUTE: /* Code 0 */
841 case ICMPV6_NOT_NEIGHBOUR: /* Code 2 */
842 case ICMPV6_ADDR_UNREACH: /* Code 3 */
843 icmp_hdr->code = ICMP_HOST_UNREACH; /* To Code 1 */
844 break;
845 case ICMPV6_ADM_PROHIBITED: /* Code 1 */
846 icmp_hdr->code = ICMP_HOST_ANO; /* To Code 10 */
847 break;
848 case ICMPV6_PORT_UNREACH: /* Code 4 */
849 icmp_hdr->code = ICMP_PORT_UNREACH; /* To Code 3 */
850
851 break;
852 default: /* discard any other codes */
853 PDEBUG("ip6_ip4(): Unknown ICMPv6 Type %d Code %d - packet dropped.\n",
854 ICMPV6_DEST_UNREACH, icmp6_hdr->icmp6_code);
855 return -1;
856 }
857 break;
858 /* Packet Too Big (Type 2) */
859 case ICMPV6_PKT_TOOBIG: /* Type 2 */
860 icmp_hdr->type = ICMP_DEST_UNREACH; /* to Type 3 */
861 icmp_hdr->code = ICMP_FRAG_NEEDED; /* to Code 4 */
862 /* Change MTU, RFC 2765 (SIIT), 4.2:
863 The MTU field needs to be adjusted for the difference between
864 the IPv4 and IPv6 header sizes taking into account whether or
865 not the packet in error includes a Fragment header.
866 */
867 /* !!! Don't implement !!! */
868 icmp_hdr->un.frag.mtu = (__u16) icmp6_hdr->icmp6_mtu;
869 break;
870 /* Time Exceeded (Type 3) */
871 case ICMPV6_TIME_EXCEED:
872 icmp_hdr->type = ICMP_TIME_EXCEEDED; /* to Type 11 */
873 icmp_hdr->code = icmp6_hdr->icmp6_code; /* Code unchanged */
874 break;
875 /* Parameter Problem (Type 4) */
876 case ICMPV6_PARAMPROB:
877 switch (icmp6_hdr->icmp6_code) {
878 case ICMPV6_UNK_NEXTHDR: /* Code 1 */
879 icmp_hdr->type = ICMP_DEST_UNREACH; /* to Type 3 */
880 icmp_hdr->code = ICMP_PROT_UNREACH; /* to Code 2 */
881 break;
882 default: /* if Code != 1 */
883 icmp_hdr->type = ICMP_PARAMETERPROB; /* to Type 12 */
884 icmp_hdr->code = 0; /* to Code 0 */
885 /* Update Pointer field
886 RFC 2765 (SIIT), 4.2:
887 The Pointer needs to be updated to point to the corresponding
888 field in the translated include IP header.
889 */
890 switch (ntohl(icmp6_hdr->icmp6_pointer))
891 {
892 case 0: /* IPv6 Version -> IPv4 Version */
893 icmp_hdr->un.echo.id = 0;
894 break;
895 case 4: /* IPv6 PayloadLength -> IPv4 Total Length */
896 icmp_hdr->un.echo.id = 0x0002; /* 2 */
897 break;
898 case 6: /* IPv6 Next Header-> IPv4 Protocol */
899 icmp_hdr->un.echo.id = 0x0009; /* 9 */
900 break;
901 case 7: /* IPv6 Hop Limit -> IPv4 TTL */
902 icmp_hdr->un.echo.id = 0x0008; /* 8 */
903 break;
904 case 8: /* IPv6 Src addr -> IPv4 Src addr */
905 icmp_hdr->un.echo.id = 0x000c; /* 12 */
906 break;
907 case 24: /* IPv6 Dst addr -> IPv4 Dst addr*/
908 icmp_hdr->un.echo.id = 0x0010; /* 16 */
909 break;
910 default: /* set all ones in other cases */
911 icmp_hdr->un.echo.id = 0xff;
912 break;
913 }
914 break;
915 }
916 break;
917
918 /* End of ICMP Error messages */
919
920 /* Echo Request and Echo Reply (Type 128 and 129) */
921 case ICMPV6_ECHO_REQUEST:
922 icmperr = 0; /* not error ICMP message */
923 icmp_hdr->type = ICMP_ECHO; /* to Type 8 */
924 icmp_hdr->code = 0; /* to Code 0 */
925 icmp_hdr->un.echo.id = icmp6_hdr->icmp6_identifier;
926 icmp_hdr->un.echo.sequence = icmp6_hdr->icmp6_sequence;
927 /* copy rest of ICMP data to result packet */
928 if (len_delta > 0)
929 memcpy(((char *)icmp_hdr) + sizeof(struct icmphdr),
930 ((char *)icmp6_hdr) + sizeof(struct icmp6hdr), len_delta);
931 break;
932 case ICMPV6_ECHO_REPLY:
933 icmperr = 0; /* not error ICMP message */
934 icmp_hdr->type = ICMP_ECHOREPLY; /* to Type 0 */
935 icmp_hdr->code = 0; /* to Code 0 */
936 icmp_hdr->un.echo.id = icmp6_hdr->icmp6_identifier;
937 icmp_hdr->un.echo.sequence = icmp6_hdr->icmp6_sequence;
938 /* copy rest of ICMP data */
939 if (len_delta > 0)
940 memcpy(((char *)icmp_hdr) + sizeof(struct icmphdr),
941 ((char *)icmp6_hdr) + sizeof(struct icmp6hdr), len_delta);
942 break;
943 default:
944 /* Unknown error messages. Silently drop. */
945 PDEBUG("ip6_ip4(): unknown ICMPv6 Type %d, packet dropped.\n", icmp6_hdr->icmp6_type);
946 return -1;
947 }
948
949 if (icmperr)
950 {
951 /* If ICMP Error message, we translate IP included packet*/
952 if (len_delta >= sizeof(struct ipv6hdr))
953 {
954 if((inc_opts_len = ip6_ip4((char *)icmp6_hdr + sizeof(struct icmp6hdr), len_delta,
955 (char *)icmp_hdr + sizeof(struct icmphdr), 1)) == -1) {
956 PDEBUG("ip6_ip4(): incorrect translation of ICMPv6 Error message, packet dropped\n");
957 return -1;
958 }
959 /* correct IPv4 Total Len that = old Total Len
960 - Options Headers Len in included IP packet
961 - diffirence between IPv6 Header Len and IPv4 Header Len
962 */
963 if (ntot_len != 0)
964 ip_hdr->tot_len = htons(ntot_len - inc_opts_len - IP4_IP6_HDR_DIFF);
965 real_len = real_len - inc_opts_len - IP4_IP6_HDR_DIFF;
966 }
967 else if (len_delta > 0)
968 {
969 /* May be it need set 0x0 to rest area in result IPv4 packet,
970 * but we copy rest data unchanged
971 */
972 memcpy(((char *)icmp_hdr) + sizeof(struct icmphdr),
973 ((char *)icmp6_hdr) + sizeof(struct icmp6hdr), len_delta);
974 }
975 }
976
977 /* Calculate IPv4 Header checksum */
978 ip_hdr->check = 0;
979 ip_hdr->check = ip_fast_csum((unsigned char *)ip_hdr, ip_hdr->ihl);
980
981 /* Calculate ICMPv4 checksum */
982 if (ntot_len != 0)
983 {
984 icmp_hdr->checksum = 0;
985 icmp_hdr->checksum = ip_compute_csum((unsigned char *)icmp_hdr, ntohs(ip_hdr->tot_len)
986 - sizeof(struct iphdr));
987 }
988 }
989 else
990 {
991 PDEBUG("ip6_ip4(): error length ICMP packet, packet dropped.\n");
992 return -1;
993 }
994
995 }
996 /* PROCESS TCP and UDP (and rest data) */
997
998 else {
999 real_len += len_delta;
1000 /* we copy rest data to IPv4 packet without changing */
1001 memcpy(dst+sizeof(struct iphdr), src + sizeof(struct ipv6hdr) + opts_len, len_delta);
1002 }
1003 }
1004
1005 if (include_flag) /* if it's included IP packet */
1006 return opts_len; /* return options headers length */
1007 else
1008 return real_len; /* result packet len */
1009 }
1010
1011 /*
1012 * ip4_fragment(skb, len, hdr_len, dev, eth_h)
1013 * to fragment original IPv4 packet if result IPv6 packet will be > 1280
1014 */
1015
1016 static int ip4_fragment(struct sk_buff *skb, int len, int hdr_len, struct net_device *dev, struct ethhdr *eth_h)
1017 {
1018 struct sk_buff *skb2 = NULL; /* pointer to new struct sk_buff for transleded packet */
1019 char buff[FRAG_BUFF_SIZE+hdr_len]; /* buffer to form new fragment packet */
1020 char *cur_ptr = skb->data+hdr_len; /* pointter to current packet data with len = frag_len */
1021 struct iphdr *ih4 = (struct iphdr *) skb->data;
1022 struct iphdr *new_ih4 = (struct iphdr *) buff; /* point to new IPv4 hdr */
1023 struct ethhdr *new_eth_h; /* point to ether hdr, need to set hard header data in fragment */
1024 int data_len = len - hdr_len; /* origin packet data len */
1025 int rest_len = data_len; /* rest data to fragment */
1026 int frag_len = 0; /* current fragment len */
1027 int last_frag = 0; /* last fragment flag, if = 1, it's last fragment */
1028 int flag_last_mf = 0;
1029 __u16 new_id = 0; /* to generate identification field */
1030 __u16 frag_offset = 0; /* fragment offset */
1031 unsigned int csum;
1032 unsigned short udp_len;
1033
1034 #ifdef SIIT_DEBUG
1035 printk("siit: it's DF == 0 and result IPv6 packet will be > 1280\n");
1036 siit_print_dump(skb->data, hdr_len, "siit: (orig) ipv4_hdr dump");
1037 #endif
1038
1039 if ((ntohs(ih4->frag_off) & IP_MF) == 0 )
1040 /* it's a case we'll clear MF flag in our last packet */
1041 flag_last_mf = 1;
1042
1043 if (ih4->protocol == IPPROTO_UDP) {
1044 if ( (ntohs(ih4->frag_off) & IP_OFFSET) == 0) {
1045 struct udphdr *udp_hdr = (struct udphdr *)((char *)ih4 + hdr_len);
1046 if (!flag_last_mf) {
1047 if (udp_hdr->check == 0) {
1048 /* it's a first fragment with ZERO checksum and we drop packet */
1049 printk("siit: First fragment of UDP with zero checksum - packet droped\n");
1050 printk("siit: addr: %x src port: %d dst port: %d\n",
1051 htonl(ih4->saddr), htons(udp_hdr->source), htons(udp_hdr->dest));
1052 return -1;
1053 }
1054 }
1055 else if (udp_hdr->check == 0) {
1056 /* Calculate UDP checksum only if it's not fragment */
1057 udp_len = ntohs(udp_hdr->len);
1058 csum = 0;
1059 csum = csum_partial((unsigned char *)udp_hdr, udp_len, csum);
1060 udp_hdr->check = csum_tcpudp_magic(ih4->saddr, ih4->daddr, udp_len, IPPROTO_UDP, csum);
1061 }
1062 }
1063 }
1064
1065 frag_offset = ntohs(ih4->frag_off) & IP_OFFSET;
1066
1067 new_id = ih4->id;
1068
1069 while(1) {
1070 if (rest_len <= FRAG_BUFF_SIZE) {
1071 /* it's last fragmen */
1072 frag_len = rest_len; /* rest data */
1073 last_frag = 1;
1074 }
1075 else
1076 frag_len = FRAG_BUFF_SIZE;
1077
1078 /* copy IP header to buffer */
1079 memcpy(buff, skb->data, hdr_len);
1080 /* copy data to buffer with len = frag_len */
1081 memcpy(buff + hdr_len, cur_ptr, frag_len);
1082
1083 /* set id field in new IPv4 header*/
1084 new_ih4->id = new_id;
1085
1086 /* is it last fragmet */
1087 if(last_frag && flag_last_mf)
1088 /* clear MF flag */
1089 new_ih4->frag_off = htons(frag_offset & (~IP_MF));
1090 else
1091 /* set MF flag */
1092 new_ih4->frag_off = htons(frag_offset | IP_MF);
1093
1094 /* change packet total length */
1095 new_ih4->tot_len = htons(frag_len+hdr_len);
1096
1097 /* rebuild the header checksum (IP needs it) */
1098 new_ih4->check = 0;
1099 new_ih4->check = ip_fast_csum((unsigned char *)new_ih4,new_ih4->ihl);
1100
1101 /* Allocate new sk_buff to compose translated packet */
1102 skb2 = dev_alloc_skb(frag_len+hdr_len+dev->hard_header_len+IP4_IP6_HDR_DIFF+IP6_FRAGMENT_SIZE);
1103 if (!skb2) {
1104 printk(KERN_DEBUG "%s: alloc_skb failure - packet dropped.\n", dev->name);
1105 dev_kfree_skb(skb2);
1106 return -1;
1107 }
1108 /* allocate skb->data portion for IP header len, fragment data len and ether header len
1109 * and copy to head ether header from origin skb
1110 */
1111 memcpy(skb_put(skb2, frag_len+hdr_len+dev->hard_header_len+IP4_IP6_HDR_DIFF+IP6_FRAGMENT_SIZE), (char *) eth_h,
1112 dev->hard_header_len);
1113 /* correct ether header data, ether protocol field to ETH_P_IPV6 */
1114 new_eth_h = (struct ethhdr *)skb2->data;
1115 new_eth_h->h_proto = htons(ETH_P_IPV6);
1116
1117 /* reset the mac header */
1118 skb_reset_mac_header(skb2);
1119
1120 /* pull ether header from new skb->data */
1121 skb_pull(skb2, dev->hard_header_len);
1122 /* set skb protocol to IPV6 */
1123 skb2->protocol = htons(ETH_P_IPV6);
1124
1125 /* call translation function */
1126 if ( ip4_ip6(buff, frag_len+hdr_len, skb2->data, 0) == -1) {
1127 dev_kfree_skb(skb2);
1128 return -1;
1129 }
1130
1131 /*
1132 * Set needed fields in new sk_buff
1133 */
1134 skb2->dev = dev;
1135 skb2->ip_summed = CHECKSUM_UNNECESSARY;
1136 skb2->pkt_type = PACKET_HOST;
1137
1138 /* Add transmit statistic */
1139 siit_stats(dev)->tx_packets++;
1140 siit_stats(dev)->tx_bytes += skb2->len;
1141
1142 /* send packet to upper layer */
1143 netif_rx(skb2);
1144
1145 /* exit if it was last fragment */
1146 if (last_frag)
1147 break;
1148
1149 /* correct current data pointer */
1150 cur_ptr += frag_len;
1151 /* rest data len */
1152 rest_len -= frag_len;
1153 /* current fragment offset */
1154 frag_offset = (frag_offset*8 + frag_len)/8;
1155 }
1156
1157 return 0;
1158 }
1159 /*
1160 * Transmit a packet (called by the kernel)
1161 *
1162 * siit_xmit(skb, dev)
1163 *
1164 * where
1165 * skb - pointer to struct sk_buff with incomed packet
1166 * dev - pointer to struct device on which packet revieved
1167 *
1168 * Statistic:
1169 * for all incoming packes:
1170 * stats.rx_bytes+=skb->len
1171 * stats.rx_packets++
1172 * for packets we can't transle:
1173 * stats.tx_errors++
1174 * device busy:
1175 * stats.tx_errors++
1176 * for packets we can't allocate sk_buff:
1177 * stats.tx_dropped++
1178 * for outgoing packes:
1179 * stats.tx_packets++
1180 * stats.tx_bytes+=skb2->len !!! But we don't set skb2->len !!!
1181 */
1182
1183 static int siit_xmit(struct sk_buff *skb, struct net_device *dev)
1184 {
1185 struct sk_buff *skb2 = NULL;/* pointer to new struct sk_buff for transleded packet */
1186 struct ethhdr *eth_h; /* pointer to incoming Ether header */
1187 int len; /* original packets length */
1188 int new_packet_len;
1189 int skb_delta = 0; /* delta size for allocate new skb */
1190 char new_packet_buff[2048];
1191
1192 /* Check pointer to sk_buff and device structs */
1193 if (skb == NULL || dev == NULL)
1194 return -EINVAL;
1195
1196 /* Add receive statistic */
1197 siit_stats(dev)->rx_bytes += skb->len;
1198 siit_stats(dev)->rx_packets++;
1199
1200 dev->trans_start = jiffies;
1201
1202 /* Upper layer (IP) protocol forms sk_buff for outgoing packet
1203 * and sets IP header + Ether header too. IP layer sets outgoing
1204 * device in sk_buff->dev.
1205 * In function (from linux/net/core/dev.c) ther is a call to
1206 * device transmit function (dev->hard_start_xmit):
1207 *
1208 * dev_queue_xmit(struct sk_buff *skb)
1209 * {
1210 * ...
1211 * device *dev = skb->dev;
1212 * ...
1213 * dev->hard_start_xmit(skb, dev);
1214 * ...
1215 * }
1216 * We save pointer to ether header in eth_h and skb_pull ether header
1217 * from data field of skb_buff
1218 */
1219
1220 eth_h = (struct ethhdr *)skb->data; /* point to incoming packet Ether Header */
1221
1222 #ifdef SIIT_DEBUG
1223 siit_print_dump(skb->data, ETH_HLEN, "siit: eth_hdr dump");
1224 #endif
1225
1226 /* Remove hardware header from origin sk_buff */
1227 skb_pull(skb,dev->hard_header_len);
1228
1229 /*
1230 * Process IPv4 paket
1231 */
1232 if (ntohs(skb->protocol) == ETH_P_IP) {
1233 int hdr_len; /* IPv4 header length */
1234 int data_len; /* IPv4 data length */
1235 struct iphdr *ih4; /* pointer to IPv4 header */
1236 struct icmphdr *icmp_hdr; /* point to current ICMPv4 header struct */
1237
1238 ih4 = (struct iphdr *)skb->data; /* point to incoming packet's IPv4 header */
1239
1240 /* Check IPv4 Total Length */
1241 if (skb->len != ntohs(ih4->tot_len)) {
1242 PDEBUG("siit_xmit(): Different skb_len %x and ip4 tot_len %x - packet dropped.\n",
1243 skb->len, ih4->tot_len);
1244 siit_stats(dev)->tx_errors++;
1245 dev_kfree_skb(skb);
1246 return 0;
1247 }
1248
1249 len = skb->len; /* packet's total len */
1250 hdr_len = (int)(ih4->ihl * 4); /* packet's header len */
1251 data_len = len - hdr_len; /* packet's data len */
1252
1253 /* If DF == 0 */
1254 if ( (ntohs(ih4->frag_off) & IP_DF) == 0 ) {
1255 /* If result IPv6 packet will be > 1280
1256 we need to fragment original IPv4 packet
1257 */
1258 if ( data_len > FRAG_BUFF_SIZE ) {
1259 /* call function that fragment packet and translate to IPv6 each fragment
1260 * and send to upper layer
1261 */
1262 if ( ip4_fragment(skb, len, hdr_len, dev, eth_h) == -1) {
1263 siit_stats(dev)->tx_errors++;
1264 }
1265 /* Free incoming skb */
1266 dev_kfree_skb(skb);
1267 /* Device can accept a new packet */
1268
1269 return 0;
1270
1271 }
1272 }
1273 /* If DF == 1 && MF == 0 && Fragment Offset == 0
1274 * we don't include fragment header
1275 */
1276 if ( ntohs(ih4->frag_off) == IP_DF )
1277 skb_delta = IP4_IP6_HDR_DIFF; /* delta is +20 */
1278 else
1279 skb_delta = IP4_IP6_HDR_DIFF + IP6_FRAGMENT_SIZE; /* delta is +20 and +8 */
1280
1281 /* If it's ICMP, check is it included IP packet in it */
1282 if ( ih4->protocol == IPPROTO_ICMP) {
1283 icmp_hdr = (struct icmphdr *) (skb->data+hdr_len); /* point to ICMPv4 header */
1284 if ( icmp_hdr->type != ICMP_ECHO && icmp_hdr->type != ICMP_ECHOREPLY) {
1285 /*
1286 * It's ICMP Error that has included IP packet
1287 * we'll add only +20 because we don't include Fragment Header
1288 * into translated included IP packet
1289 */
1290 skb_delta += IP4_IP6_HDR_DIFF;
1291 }
1292 }
1293
1294 /* Allocate new sk_buff to compose translated packet */
1295 skb2 = dev_alloc_skb(len+dev->hard_header_len+skb_delta);
1296 if (!skb2) {
1297 printk(KERN_DEBUG "%s: alloc_skb failure - packet dropped.\n", dev->name);
1298 dev_kfree_skb(skb);
1299 siit_stats(dev)->rx_dropped++;
1300
1301 return 0;
1302 }
1303 /* allocate skb->data portion = IPv4 packet len + ether header len
1304 * + skb_delta (max = two times (diffirence between IPv4 header and
1305 * IPv6 header + Frag Header), second for included packet,
1306 * and copy to head of skb->data ether header from origin skb
1307 */
1308 memcpy(skb_put(skb2, len+dev->hard_header_len+skb_delta), (char *)eth_h, dev->hard_header_len);
1309 /* correct ether header data, ether protocol field to ETH_P_IPV6 */
1310 eth_h = (struct ethhdr *)skb2->data;
1311 eth_h->h_proto = htons(ETH_P_IPV6);
1312 skb_reset_mac_header(skb2);
1313 /* remove ether header from new skb->data,
1314 * NOTE! data will rest, pointer to data and data len will change
1315 */
1316 skb_pull(skb2,dev->hard_header_len);
1317 /* set skb protocol to IPV6 */
1318 skb2->protocol = htons(ETH_P_IPV6);
1319
1320 /* call translation function */
1321 if (ip4_ip6(skb->data, len, skb2->data, 0) == -1 ) {
1322 dev_kfree_skb(skb);
1323 dev_kfree_skb(skb2);
1324 siit_stats(dev)->rx_errors++;
1325
1326 return 0;
1327 }
1328 }
1329 /*
1330 * IPv6 paket
1331 */
1332 else if (ntohs(skb->protocol) == ETH_P_IPV6) {
1333
1334 #ifdef SIIT_DEBUG
1335 siit_print_dump(skb->data, sizeof(struct ipv6hdr), "siit: (in) ip6_hdr dump");
1336 #endif
1337 /* packet len = skb->data len*/
1338 len = skb->len;
1339
1340 /* call translation function */
1341 if ((new_packet_len = ip6_ip4(skb->data, len, new_packet_buff, 0)) == -1 )
1342 {
1343 PDEBUG("siit_xmit(): error translation ipv6->ipv4, packet dropped.\n");
1344 siit_stats(dev)->rx_dropped++;
1345 goto end;
1346 }
1347
1348 /* Allocate new sk_buff to compose translated packet */
1349 skb2 = dev_alloc_skb(new_packet_len + dev->hard_header_len);
1350 if (!skb2) {
1351 printk(KERN_DEBUG "%s: alloc_skb failure, packet dropped.\n", dev->name);
1352 siit_stats(dev)->rx_dropped++;
1353 goto end;
1354 }
1355 memcpy(skb_put(skb2, new_packet_len + dev->hard_header_len), (char *)eth_h, dev->hard_header_len);
1356 eth_h = (struct ethhdr *)skb2->data;
1357 eth_h->h_proto = htons(ETH_P_IP);
1358 skb_reset_mac_header(skb2);
1359 skb_pull(skb2, dev->hard_header_len);
1360 memcpy(skb2->data, new_packet_buff, new_packet_len);
1361 skb2->protocol = htons(ETH_P_IP);
1362 }
1363 else {
1364 PDEBUG("siit_xmit(): unsupported protocol family %x, packet dropped.\n", skb->protocol);
1365 goto end;
1366 }
1367
1368 /*
1369 * Set needed fields in new sk_buff
1370 */
1371 skb2->pkt_type = PACKET_HOST;
1372 skb2->dev = dev;
1373 skb2->ip_summed = CHECKSUM_UNNECESSARY;
1374
1375 /* Add transmit statistic */
1376 siit_stats(dev)->tx_packets++;
1377 siit_stats(dev)->tx_bytes += skb2->len;
1378
1379 /* Send packet to upper layer protocol */
1380 netif_rx(skb2);
1381
1382 end:
1383 dev_kfree_skb(skb);
1384
1385 return 0;
1386 }
1387
1388 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0)
1389 static bool header_ops_init = false;
1390 static struct header_ops siit_header_ops ____cacheline_aligned;
1391 #endif
1392
1393 #if !(defined CONFIG_COMPAT_NET_DEV_OPS) && LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,30)
1394 static const struct net_device_ops siit_netdev_ops = {
1395 .ndo_open = siit_open,
1396 .ndo_stop = siit_release,
1397 .ndo_start_xmit = siit_xmit,
1398 };
1399 #endif
1400
1401 /*
1402 * The init function initialize of the SIIT device..
1403 * It is invoked by register_netdev()
1404 */
1405
1406 static void
1407 siit_init(struct net_device *dev)
1408 {
1409 ether_setup(dev); /* assign some of the fields */
1410 random_ether_addr(dev->dev_addr);
1411
1412 /*
1413 * Assign device function.
1414 */
1415 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30)
1416 dev->open = siit_open;
1417 dev->stop = siit_release;
1418 dev->hard_start_xmit = siit_xmit;
1419 #else
1420 #if !(defined CONFIG_COMPAT_NET_DEV_OPS) && LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,30)
1421 dev->netdev_ops = &siit_netdev_ops;
1422 #endif
1423 #endif
1424 dev->flags |= IFF_NOARP; /* ARP not used */
1425 dev->tx_queue_len = 10;
1426
1427 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
1428 dev->hard_header_cache = NULL; /* Disable caching */
1429 memset(netdev_priv(dev), 0, sizeof(struct net_device_stats));
1430 dev->get_stats = siit_get_stats;
1431 #else
1432 if (!header_ops_init) {
1433 memcpy(&siit_header_ops, dev->header_ops, sizeof(struct header_ops));
1434 siit_header_ops.cache = NULL;
1435 }
1436 dev->header_ops = &siit_header_ops;
1437 #endif
1438 }
1439
1440 /*
1441 * Finally, the module stuff
1442 */
1443 static struct net_device *siit_dev = NULL;
1444
1445 int init_module(void)
1446 {
1447 int res = -ENOMEM;
1448 int priv_size;
1449
1450 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
1451 priv_size = sizeof(struct net_device_stats);
1452 #else
1453 priv_size = sizeof(struct header_ops);
1454 #endif
1455 siit_dev = alloc_netdev(priv_size, "siit%d", siit_init);
1456 if (!siit_dev)
1457 goto err_alloc;
1458
1459 res = register_netdev(siit_dev);
1460 if (res)
1461 goto err_register;
1462
1463 return 0;
1464
1465 err_register:
1466 free_netdev(siit_dev);
1467 err_alloc:
1468 printk(KERN_ERR "Error creating siit device: %d\n", res);
1469 return res;
1470 }
1471
1472 void cleanup_module(void)
1473 {
1474 unregister_netdev(siit_dev);
1475 free_netdev(siit_dev);
1476 }
1477
1478
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