diff options
Diffstat (limited to 'package/siit/src/siit.c')
| -rw-r--r-- | package/siit/src/siit.c | 1478 |
1 files changed, 1478 insertions, 0 deletions
diff --git a/package/siit/src/siit.c b/package/siit/src/siit.c new file mode 100644 index 000000000..5362c1daa --- /dev/null +++ b/package/siit/src/siit.c @@ -0,0 +1,1478 @@ +/* + * siit.c: the Stateless IP/ICMP Translator (SIIT) module for Linux. + * + * + */ + +#include <linux/version.h> +#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,33)) +#include <generated/autoconf.h> +#else +#include <linux/autoconf.h> +#endif +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/kernel.h> /* printk() */ +#include <linux/slab.h> + +#include <linux/errno.h> /* error codes */ +#include <linux/types.h> /* size_t */ +#include <linux/interrupt.h> /* mark_bh */ +#include <linux/random.h> +#include <linux/in.h> +#include <linux/netdevice.h> /* struct device, and other headers */ +#include <linux/etherdevice.h> /* eth_type_trans */ +#include <net/ip.h> /* struct iphdr */ +#include <net/icmp.h> /* struct icmphdr */ +#include <net/ipv6.h> +#include <net/udp.h> +#include <linux/skbuff.h> +#include <linux/in6.h> +#include <linux/init.h> +#include <asm/uaccess.h> +#include <asm/checksum.h> +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) +#include <net/ip6_checksum.h> +#endif +#include <linux/in6.h> +#include "siit.h" + +MODULE_AUTHOR("Dmitriy Moscalev, Grigory Klyuchnikov, Felix Fietkau"); + +/* + * If tos_ignore_flag != 0, we don't copy TOS and Traffic Class + * from origin paket and set it to 0 + */ +int tos_ignore_flag = 0; + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) +static inline void +skb_reset_mac_header(struct sk_buff *skb) +{ + skb->mac.raw=skb->data; +} + +static struct net_device_stats * +siit_get_stats(struct net_device *dev) +{ + return netdev_priv(dev); +} + +static inline void random_ether_addr(u8 *addr) +{ + get_random_bytes (addr, ETH_ALEN); + addr [0] &= 0xfe; /* clear multicast bit */ + addr [0] |= 0x02; /* set local assignment bit (IEEE802) */ +} + + +#define siit_stats(_dev) ((struct net_device_stats *)netdev_priv(_dev)) +#else +#define siit_stats(_dev) (&(_dev)->stats) +#endif + +/* + * The Utility stuff + */ + +#ifdef SIIT_DEBUG +/* print dump bytes (data point data area sizeof len and message + * before dump. + */ +static int siit_print_dump(char *data, int len, char *message) +{ + int i; + int j = 0, k = 1; + + len = len > BUFF_SIZE ? BUFF_SIZE : len; + printk("%s:\n", message); + for (i=0; i < len; i++, k++) { + if( i == len-1 || k == 16) { + printk("%02x\n", (~(~0 << 8) & *(data+i))); + j = 0; + k = 0; + } + else if (j) { + printk("%02x ", (~(~0 << 8) & *(data+i))); + j--; + } + else { + printk("%02x", (~(~0 << 8) & *(data+i))); + j++; + } + } + return 0; +} +#endif + +/* + * Open and close + */ +static int siit_open(struct net_device *dev) +{ + netif_start_queue(dev); + return 0; +} + + +static int siit_release(struct net_device *dev) +{ + netif_stop_queue(dev); /* can't transmit any more */ + return 0; +} + +/* + * Translation IPv4 to IPv6 stuff + * + * ip4_ip6 (src, len, dst, include_flag) + * + * where + * src - buffer with original IPv4 packet, + * len - size of original packet, + * dst - new buffer for IPv6 packet, + * include_flag - if = 1, dst point to IPv4 packet that is ICMP error + * included IP packet, else = 0 + */ + +static int ip4_ip6(char *src, int len, char *dst, int include_flag) +{ + struct iphdr *ih4 = (struct iphdr *) src; /* point to current IPv4 header struct */ + struct icmphdr *icmp_hdr; /* point to current ICMPv4 header struct */ + struct udphdr *udp_hdr; /* point to current IPv4 UDP header struct */ + + struct ipv6hdr *ih6 = (struct ipv6hdr *) dst; /* point to current IPv6 header struct */ + struct frag_hdr *ih6_frag = (struct frag_hdr *)(dst+sizeof(struct ipv6hdr)); + /* point to current IPv6 fragment header struct */ + struct icmp6hdr *icmp6_hdr; /* point to current ICMPv6 header */ + + int hdr_len = (int)(ih4->ihl * 4); /* IPv4 header length */ + int icmp_len; /* ICMPv4 packet length */ + int plen; /* payload length */ + + unsigned int csum; /* need to calculate ICMPv6 and UDP checksum */ + int fl_csum = 0; /* flag to calculate UDP checksum */ + int icmperr = 1; /* flag to indicate ICMP error message and to need + translate ICMP included IP packet */ + int fr_flag = 0; /* fragment flag, if = 0 - don't add + fragment header */ + __u16 new_tot_len; /* need to calculate IPv6 total length */ + __u8 new_nexthdr; /* next header code */ + __u16 icmp_ptr = 0; /* Pointer field in ICMP_PARAMETERPROB */ + +#ifdef SIIT_DEBUG /* print IPv4 header dump */ + siit_print_dump(src, hdr_len, "siit: ip4_ip6() (in) ip4 header dump"); +#endif + + /* If DF == 1 && MF == 0 && Fragment Offset == 0 + * or this packet is ICMP included IP packet + * we don't need fragment header */ + if (ntohs(ih4->frag_off) == IP_DF || include_flag ) { + /* not fragment and we need not to add Fragment + * Header to IPv6 packet. */ + /* total length = total length from IPv4 packet */ + new_tot_len = ntohs(ih4->tot_len); + + if (ih4->protocol == IPPROTO_ICMP) + new_nexthdr = NEXTHDR_ICMP; + else + new_nexthdr = ih4->protocol; + } + else { + /* need to add Fragment Header */ + fr_flag = 1; + /* total length = total length from IPv4 packet + + length of Fragment Header */ + new_tot_len = ntohs(ih4->tot_len) + sizeof(struct frag_hdr); + /* IPv6 Header NextHeader = NEXTHDR_FRAGMENT */ + new_nexthdr = NEXTHDR_FRAGMENT; + /* Fragment Header NextHeader copy from IPv4 packet */ + if (ih4->protocol == IPPROTO_ICMP) + ih6_frag->nexthdr = NEXTHDR_ICMP; + else + ih6_frag->nexthdr = ih4->protocol; + + /* copy frag offset from IPv4 packet */ + ih6_frag->frag_off = htons((ntohs(ih4->frag_off) & IP_OFFSET) << 3); + /* copy MF flag from IPv4 packet */ + ih6_frag->frag_off = htons((ntohs(ih6_frag->frag_off) | + ((ntohs(ih4->frag_off) & IP_MF) >> 13))); + /* copy Identification field from IPv4 packet */ + ih6_frag->identification = htonl(ntohs(ih4->id)); + /* reserved field initialized to zero */ + ih6_frag->reserved = 0; + } + + /* Form rest IPv6 fields */ + + /* + * At this point we need to add checking of unxpired source + * route optin and if it is, send ICMPv4 "destination + * unreacheble/source route failes" Type 3/Code 5 and + * drop packet. (NOT RELEASED YET) + */ + + /* IP version = 6 */ + ih6->version = 6; + + if (tos_ignore_flag) { + ih6->priority = 0; + ih6->flow_lbl[0] = 0; + } else { + ih6->priority = (ih4->tos & 0xf0) >> 4; + ih6->flow_lbl[0] = (ih4->tos & 0x0f) << 4; + } + ih6->flow_lbl[1] = 0; + ih6->flow_lbl[2] = 0; + + /* Hop Limit = IPv4 TTL */ + ih6->hop_limit = ih4->ttl; + + /* Translate source destination addresses, + for IPv6 host it's IPv4-translated IPv6 address, + for IPv4 host it's IPv4-mapped IPv6 address + + !!WARNING!! Instead IPv4-mapped IPv6 addresses we use addreesses + with unused prefix ::ffff:ffff:0:0/96, because KAME implementation + doesn't support IPv4-mapped addresses in IPv6 packets and discard them. + + */ + + if (include_flag) { + /* + It's ICMP included IP packet and there is a diffirence + in src/dst addresses then src/dst in normal direction + */ + + /* + Source address + is IPv4-translated IPv6 address because packet traveled + from IPv6 to IPv4 area + */ + ih6->saddr.in6_u.u6_addr32[0] = 0; + ih6->saddr.in6_u.u6_addr32[1] = 0; + ih6->saddr.in6_u.u6_addr32[2] = htonl(TRANSLATED_PREFIX); /* to network order bytes */ + ih6->saddr.in6_u.u6_addr32[3] = ih4->saddr; + + /* + Destination address + is IPv4-mapped address (but it's not IPv4- mapped, we use + prefix ::ffff:ffff:0:0/96 + */ + ih6->daddr.in6_u.u6_addr32[0] = 0; + ih6->daddr.in6_u.u6_addr32[1] = 0; + ih6->daddr.in6_u.u6_addr32[2] = htonl(MAPPED_PREFIX); /* to network order bytes */ + ih6->daddr.in6_u.u6_addr32[3] = ih4->daddr; + } + else { + + /* + This is normal case (packet isn't included IP packet) + + Source address + is IPv4-mapped address (but it's not IPv4- mapped, we use + prefix ::ffff:ffff:0:0/96) + */ + ih6->saddr.in6_u.u6_addr32[0] = 0; + ih6->saddr.in6_u.u6_addr32[1] = 0; + ih6->saddr.in6_u.u6_addr32[2] = htonl(MAPPED_PREFIX); /* to network order bytes */ + ih6->saddr.in6_u.u6_addr32[3] = ih4->saddr; + + /* Destination address + is is IPv4-translated IPv6 address + */ + ih6->daddr.in6_u.u6_addr32[0] = 0; + ih6->daddr.in6_u.u6_addr32[1] = 0; + ih6->daddr.in6_u.u6_addr32[2] = htonl(TRANSLATED_PREFIX); /* to network order bytes */ + ih6->daddr.in6_u.u6_addr32[3] = ih4->daddr; + } + + /* Payload Length */ + plen = new_tot_len - hdr_len; /* Payload length = IPv4 total len - IPv4 header len */ + ih6->payload_len = htons(plen); + + /* Next Header */ + ih6->nexthdr = new_nexthdr; /* Next Header */ + + /* Process ICMP protocols data */ + + switch (ih4->protocol) { + case IPPROTO_ICMP: + if ( (ntohs(ih4->frag_off) & IP_OFFSET) != 0 || (ntohs(ih4->frag_off) & IP_MF) != 0 ) { + PDEBUG("ip4_ip6(): don't translate ICMPv4 fragments - packet dropped.\n"); + return -1; + } + + icmp_hdr = (struct icmphdr *) (src+hdr_len); /* point to ICMPv4 header */ + csum = 0; + icmp_len = ntohs(ih4->tot_len) - hdr_len; /* ICMPv4 packet length */ + icmp6_hdr = (struct icmp6hdr *)(dst+sizeof(struct ipv6hdr) + +fr_flag*sizeof(struct frag_hdr)); /* point to ICMPv6 header */ + + if (include_flag) { + /* ICMPv4 packet cannot be included in ICMPv4 Error message */ + /* !!! May be it's WRONG !!! ICMPv4 QUERY packet can be included + in ICMPv4 Error message */ + PDEBUG("ip4_ip6(): It's included ICMPv4 in ICMPv4 Error message - packet dropped.\n"); + return -1; + } + + /* Check ICMPv4 Type field */ + switch (icmp_hdr->type) { + /* ICMP Error messages */ + /* Destination Unreachable (Type 3) */ + case ICMP_DEST_UNREACH: + icmp6_hdr->icmp6_type = ICMPV6_DEST_UNREACH; /* to Type 1 */ + icmp6_hdr->icmp6_unused = 0; + switch (icmp_hdr->code) + { + case ICMP_NET_UNREACH: /* Code 0 */ + case ICMP_HOST_UNREACH: /* Code 1 */ + case ICMP_SR_FAILED: /* Code 5 */ + case ICMP_NET_UNKNOWN: /* Code 6 */ + case ICMP_HOST_UNKNOWN: /* Code 7 */ + case ICMP_HOST_ISOLATED: /* Code 8 */ + case ICMP_NET_UNR_TOS: /* Code 11 */ + case ICMP_HOST_UNR_TOS: /* Code 12 */ + icmp6_hdr->icmp6_code = ICMPV6_NOROUTE; /* to Code 0 */ + break; + case ICMP_PROT_UNREACH: /* Code 2 */ + icmp6_hdr->icmp6_type = ICMPV6_PARAMPROB; /* to Type 4 */ + icmp6_hdr->icmp6_code = ICMPV6_UNK_NEXTHDR; /* to Code 1 */ + /* Set pointer filed to 6, it's octet offset IPv6 Next Header field */ + icmp6_hdr->icmp6_pointer = htonl(6); + break; + case ICMP_PORT_UNREACH: /* Code 3 */ + icmp6_hdr->icmp6_code = ICMPV6_PORT_UNREACH; /* to Code 4 */ + break; + case ICMP_FRAG_NEEDED: /* Code 4 */ + icmp6_hdr->icmp6_type = ICMPV6_PKT_TOOBIG; /* to Type 2 */ + icmp6_hdr->icmp6_code = 0; + /* Correct MTU */ + if (icmp_hdr->un.frag.mtu == 0) + /* we use minimum MTU for IPv4 PMTUv4 RFC1191, section 5; + IPv6 implementation wouldn't accept Path MTU < 1280, + but it records info correctly to always include + a fragment header */ + icmp6_hdr->icmp6_mtu = htonl(576); + else + /* needs to adjusted for difference between IPv4/IPv6 headers + * SIIT RFC2765, section 3.3, + * we assume that difference is 20 bytes */ + icmp6_hdr->icmp6_mtu = htonl(ntohs(icmp_hdr->un.frag.mtu)+IP4_IP6_HDR_DIFF); + + break; + case ICMP_NET_ANO: /* Code 9 */ + case ICMP_HOST_ANO: /* Code 10 */ + icmp6_hdr->icmp6_code = ICMPV6_ADM_PROHIBITED; /* to Code 1 */ + break; + default: /* discard any other Code */ + PDEBUG("ip4_ip6(): Unknown ICMPv4 Type %d Code %d - packet dropped.\n", + ICMP_DEST_UNREACH, icmp_hdr->code); + return -1; + } + break; + /* Time Exceeded (Type 11) */ + case ICMP_TIME_EXCEEDED: + icmp6_hdr->icmp6_type = ICMPV6_TIME_EXCEED; + icmp6_hdr->icmp6_code = icmp_hdr->code; + break; + /* Parameter Problem (Type 12) */ + case ICMP_PARAMETERPROB: + icmp6_hdr->icmp6_type = ICMPV6_PARAMPROB; + icmp6_hdr->icmp6_code = icmp_hdr->code; + + icmp_ptr = ntohs(icmp_hdr->un.echo.id) >> 8; + switch (icmp_ptr) { + case 0: + icmp6_hdr->icmp6_pointer = 0; /* IPv4 Version -> IPv6 Version */ + break; + case 2: + icmp6_hdr->icmp6_pointer = __constant_htonl(4); /* IPv4 length -> IPv6 Payload Length */ + break; + case 8: + icmp6_hdr->icmp6_pointer = __constant_htonl(7); /* IPv4 TTL -> IPv6 Hop Limit */ + break; + case 9: + icmp6_hdr->icmp6_pointer = __constant_htonl(6); /* IPv4 Protocol -> IPv6 Next Header */ + break; + case 12: + icmp6_hdr->icmp6_pointer = __constant_htonl(8); /* IPv4 Src Addr -> IPv6 Src Addr */ + break; + case 16: + icmp6_hdr->icmp6_pointer = __constant_htonl(24); /* IPv4 Dst Addr -> IPv6 Dst Addr */ + break; + default: + icmp6_hdr->icmp6_pointer = 0xffffffff; /* set to all ones in any other cases */ + break; + } + break; + case ICMP_ECHO: + icmperr = 0; + icmp6_hdr->icmp6_type = ICMPV6_ECHO_REQUEST; + icmp6_hdr->icmp6_code = 0; + /* Copy rest ICMP data to new IPv6 packet without changing */ + memcpy(((char *)icmp6_hdr)+4, ((char *)icmp_hdr)+4, len - hdr_len - 4); + break; + + case ICMP_ECHOREPLY: + icmperr = 0; + icmp6_hdr->icmp6_type = ICMPV6_ECHO_REPLY; + icmp6_hdr->icmp6_code = 0; + /* Copy rest ICMP data to new IPv6 packet without changing */ + memcpy(((char *)icmp6_hdr)+4, ((char *)icmp_hdr)+4, len - hdr_len - 4); + break; + + /* Discard any other ICMP messages */ + default: + PDEBUG("ip4_ip6(): Unknown ICMPv4 packet Type %x - packet dropped.\n", icmp_hdr->type); + return -1; + } + + /* Now if it's ICMPv4 Error message we must translate included IP packet */ + + if (icmperr) { + /* Call our ip4_ip6() to translate included IP packet */ + if (ip4_ip6(src+hdr_len+sizeof(struct icmphdr), len - hdr_len - sizeof(struct icmphdr), + dst+sizeof(struct ipv6hdr)+fr_flag*sizeof(struct frag_hdr) + +sizeof(struct icmp6hdr), 1) == -1) { + PDEBUG("ip4_ip6(): Uncorrect translation of ICMPv4 Error message - packet dropped.\n"); + return -1; + } + /* correct ICMPv6 packet length for diffirence between IPv4 and IPv6 headers + in included IP packet + */ + icmp_len += 20; + /* and correct Payload length for diffirence between IPv4 and IPv6 headers */ + plen += 20; + ih6->payload_len = htons(plen); + } + + /* Calculate ICMPv6 checksum */ + + icmp6_hdr->icmp6_cksum = 0; + csum = 0; + + csum = csum_partial((u_char *)icmp6_hdr, icmp_len, csum); + icmp6_hdr->icmp6_cksum = csum_ipv6_magic(&ih6->saddr, &ih6->daddr, icmp_len, + IPPROTO_ICMPV6, csum); + break; + + /* Process TCP protocols data */ + case IPPROTO_TCP: + /* Copy TCP data to new IPv6 packet without changing */ + memcpy(dst+sizeof(struct ipv6hdr)+fr_flag*sizeof(struct frag_hdr), + src+hdr_len, len - hdr_len); + break; + + /* Process UDP protocols data */ + case IPPROTO_UDP: + udp_hdr = (struct udphdr *)(src+hdr_len); + if ((ntohs(ih4->frag_off) & IP_OFFSET) == 0) { + if ((ntohs(ih4->frag_off) & IP_MF) != 0) { + /* It's a first fragment */ + if (udp_hdr->check == 0) { + /* System management event */ + printk("siit: First fragment of UDP with zero checksum - packet droped\n"); + printk("siit: addr: %x src port: %d dst port: %d\n", + htonl(ih4->saddr), htons(udp_hdr->source), htons(udp_hdr->dest)); + return -1; + } + } + else if (udp_hdr->check == 0) + fl_csum = 1; + } + + /* Copy UDP data to new IPv6 packet */ + udp_hdr = (struct udphdr *)(dst+sizeof(struct ipv6hdr) + + fr_flag*sizeof(struct frag_hdr)); + memcpy((char *)udp_hdr, src+hdr_len, len - hdr_len); + + /* Calculate UDP checksum if UDP checksum in IPv4 packet was ZERO + and if it isn't included IP packet + */ + if (fl_csum && (!include_flag)) { + udp_hdr->check = 0; + csum = 0; + csum = csum_partial((unsigned char *)udp_hdr, plen - fr_flag*sizeof(struct frag_hdr), csum); + udp_hdr->check = csum_ipv6_magic(&ih6->saddr, &ih6->daddr, plen - + fr_flag*sizeof(struct frag_hdr), IPPROTO_UDP, csum); + } + break; + + /* Discard packets with any other protocol */ + default: + PDEBUG("ip4_ip6(): Unknown upper protocol - packet dropped.\n"); + return -1; + } + +#ifdef SIIT_DEBUG + siit_print_dump(dst, sizeof(struct ipv6hdr), "siit: ip4_ip6(): (out) ipv6 header dump"); +#endif + + return 0; +} + +/* + * Translation IPv6 to IPv4 stuff + * + * ip6_ip4(src, len, dst, include_flag) + * + * where + * src - buffer with original IPv6 packet, + * len - size of original packet, + * dst - new buffer for IPv4 packet, + * include_flag - if = 1, dst point to IPv6 packet that is ICMP error + * included IP packet, else = 0 + * + */ + +static int ip6_ip4(char *src, int len, char *dst, int include_flag) +{ + struct ipv6hdr *ip6_hdr; /* point to current IPv6 header struct */ + struct iphdr *ip_hdr; /* point to current IPv4 header struct */ + int opts_len = 0; /* to sum Option Headers length */ + int icmperr = 1; /* if = 1, indicate that packet is ICMP Error message, else = 0 */ + int ntot_len = 0; /* to calculate IPv6 Total Length field */ + int real_len; + int len_delta; + int ip6_payload_len; + int inc_opts_len = 0; /* to sum Option Headers length in ICMP included IP packet */ + __u8 next_hdr; /* Next Header */ + +#ifdef SIIT_DEBUG + siit_print_dump(src, sizeof(struct ipv6hdr), "siit: ip6_ip4(): (in) ipv6 header dump"); +#endif + + if ( (len_delta = len - sizeof(struct ipv6hdr)) >= 0) + { + ip6_hdr = (struct ipv6hdr *)src; + ip_hdr = (struct iphdr *)dst; + + real_len = sizeof(struct iphdr); + + /* Check validation of Saddr & Daddr? is a packet to fall under our translation? */ + if (include_flag) { /* It's ICMP included IP packet, + about process include_flag see comment in ip4_ip6() */ + if (ip6_hdr->saddr.s6_addr32[2] != htonl(MAPPED_PREFIX)) { + PDEBUG("ip6_ip4(): Included IP packet Src addr isn't mapped addr: %x%x%x%x, packet dropped.\n", + ip6_hdr->saddr.s6_addr32[0], ip6_hdr->saddr.s6_addr32[1], + ip6_hdr->saddr.s6_addr32[2], ip6_hdr->saddr.s6_addr32[3]); + return -1; + } + if ( ip6_hdr->daddr.s6_addr32[2] != htonl(TRANSLATED_PREFIX)) { + PDEBUG("ip6_ip4(): Included IP packet Dst addr isn't translated addr: %x%x%x%x, packet dropped.\n", + ip6_hdr->daddr.s6_addr32[0], ip6_hdr->daddr.s6_addr32[1], + ip6_hdr->daddr.s6_addr32[2], ip6_hdr->daddr.s6_addr32[3]); + return -1; + } + } + else { /* It's normal IP packet (not included in ICMP) */ + if (ip6_hdr->saddr.s6_addr32[2] != htonl(TRANSLATED_PREFIX)) { + PDEBUG("ip6_ip4(): Src addr isn't translated addr: %x%x%x%x, packet dropped.\n", + ip6_hdr->saddr.s6_addr32[0], ip6_hdr->saddr.s6_addr32[1], + ip6_hdr->saddr.s6_addr32[2], ip6_hdr->saddr.s6_addr32[3]); + return -1; + } + if ( ip6_hdr->daddr.s6_addr32[2] != htonl(MAPPED_PREFIX)) { + PDEBUG("ip6_ip4(): Dst addr isn't mapped addr: %x%x%x%x, packet dropped.\n", + ip6_hdr->daddr.s6_addr32[0], ip6_hdr->daddr.s6_addr32[1], + ip6_hdr->daddr.s6_addr32[2], ip6_hdr->daddr.s6_addr32[3]); + return -1; + } + } + + /* Set IPv4 Fragment Offset and ID to 0 + before process any Option Headers */ + ip_hdr->frag_off = 0; + ip_hdr->id = 0; + + /* + * We process only Fragment Header. Any other options headers + * are ignored, i.e. there is no attempt to translate them. + * However, the Total Length field and the Protocol field would + * have to be adjusted to "skip" these extension headers. + */ + + next_hdr = ip6_hdr->nexthdr; + + /* Hop_by_Hop options header (ip6_hdr->nexthdr = 0). It must + * appear only in IPv6 header's Next Header field. + */ + if (next_hdr == NEXTHDR_HOP) { + if ( (len_delta - sizeof(struct ipv6_opt_hdr)) >= 0) + { + struct ipv6_opt_hdr *ip6h = + (struct ipv6_opt_hdr *)(src+sizeof(struct ipv6hdr) + opts_len); + if ( (len_delta -= ip6h->hdrlen*8 + 8) >= 0) + { + opts_len += ip6h->hdrlen*8 + 8; /* See RFC 2460 page 11: + Hdr Ext Len 8-bit unsigned integer. Length of the Hop-by- + Hop Options header in 8-octet units, not + including the first 8 octets. + */ + next_hdr = ip6h->nexthdr; + } + else + { + PDEBUG("ip6_ip4(): hop_by_hop header error, packet droped"); + /* Generate ICMP Parameter Problem */ + return -1; + } + } + } + + if (len_delta > 0) + { + while(next_hdr != NEXTHDR_ICMP && next_hdr != NEXTHDR_TCP + && next_hdr != NEXTHDR_UDP) + { + /* Destination options header */ + if (next_hdr == NEXTHDR_DEST) + { + if ( (len_delta - sizeof(struct ipv6_opt_hdr)) >= 0) + { + struct ipv6_opt_hdr *ip6d = + (struct ipv6_opt_hdr *)(src + sizeof(struct ipv6hdr) + opts_len); + if ( (len_delta -= ip6d->hdrlen*8 + 8) >= 0) + { + opts_len += ip6d->hdrlen*8 + 8; + next_hdr = ip6d->nexthdr; + } + } + else + { + PDEBUG("ip6_ip4(): destination header error, packet droped"); + /* Generate ICMP Parameter Problem */ + return -1; + } + } + /* Routing options header */ + else if (next_hdr == NEXTHDR_ROUTING) + { + if ( (len_delta - sizeof(struct ipv6_rt_hdr)) >= 0) + { + struct ipv6_rt_hdr *ip6rt = + (struct ipv6_rt_hdr *)(src+sizeof(struct ipv6hdr) + opts_len); + /* RFC 2765 SIIT, 4.1: + If a routing header with a non-zero Segments Left field is present + then the packet MUST NOT be translated, and an ICMPv6 "parameter + problem/ erroneous header field encountered" (Type 4/Code 0) error + message, with the Pointer field indicating the first byte of the + Segments Left field, SHOULD be returned to the sender. + */ + if (ip6rt->segments_left != 0) { + /* Build ICMPv6 "Parameter Problem/Erroneous Header + Field Encountered" & drop the packet */ + /* !!! We don't send ICMPv6 "Parameter Problem" !!! */ + PDEBUG("ip6_ip4(): routing header type != 0\n"); + return -1; + } + if ( (len_delta -= ip6rt->hdrlen*8 + 8) >= 0) + { + opts_len += ip6rt->hdrlen*8 + 8; + next_hdr = ip6rt->nexthdr; + } + else + { + PDEBUG("ip6_ip4(): routing header error, packet droped"); + /* Generate ICMP Parameter Problem */ + return -1; + } + } + } + /* Fragment options header */ + else if (next_hdr == NEXTHDR_FRAGMENT) + { + if ( (len_delta -= sizeof(struct frag_hdr)) >= 0) + { + struct frag_hdr *ip6f = + (struct frag_hdr *)(src+sizeof(struct ipv6hdr)+opts_len); + + opts_len += sizeof(struct frag_hdr); /* Frag Header Length = 8 */ + ip_hdr->id = htons(ntohl(ip6f->identification)); /* ID field */ + ip_hdr->frag_off = htons((ntohs(ip6f->frag_off) & IP6F_OFF_MASK) >> 3); + /* fragment offset */ + ip_hdr->frag_off = htons(ntohs(ip_hdr->frag_off) | + ((ntohs(ip6f->frag_off) & IP6F_MORE_FRAG) << 13)); + /* more fragments flag */ + next_hdr = ip6f->nexthdr; + } + else + { + PDEBUG("ip6_ip4(): fragment header error, packet droped"); + /* Generate ICMP Parameter Problem */ + return -1; + } + } + /* No Next Header */ + else if (next_hdr == NEXTHDR_NONE) + { + /* RFC 2460 IPv6 Specification, 4.7 + 4.7 No Next Header + + The value 59 in the Next Header field of an IPv6 header or any + extension header indicates that there is nothing following that + header. If the Payload Length field of the IPv6 header indicates the + presence of octets past the end of a header whose Next Header field + contains 59, those octets must be ignored, and passed on unchanged if + the packet is forwarded. + */ + break; + } + else if (next_hdr == NEXTHDR_ESP || next_hdr == NEXTHDR_AUTH) + { + PDEBUG("ip6_ip4(): cannot translate AUTH or ESP extention header, packet dropped\n"); + return -1; + } + else if (next_hdr == NEXTHDR_IPV6) + { + PDEBUG("ip6_ip4(): cannot translate IPv6-IPv6 packet, packet dropped\n"); + return -1; + } + else if (next_hdr == 0) + { + /* As say RFC 2460 (IPv6 Spec) we should discard the packet and send an + ICMP Parameter Problem message to the source of the packet, with an + ICMP Code value of 1 ("unrecognized Next Header type encountered") + and the ICMP Pointer field containing the offset of the unrecognized + value within the original packet + */ + /* NOT IMPLEMENTED */ + PDEBUG("ip6_ip4(): NEXTHDR in extention header = 0, packet dropped\n"); + return -1; + } + else + { + PDEBUG("ip6_ip4(): cannot translate extention header = %d, packet dropped\n", next_hdr); + return -1; + } + } + } + } + else + { + PDEBUG("ip6_ip4(): error packet len, packet dropped.\n"); + return -1; + } + + /* Building ipv4 packet */ + + ip_hdr->version = IPVERSION; + ip_hdr->ihl = 5; + + /* TOS see comment about TOS in ip4_ip6() */ + if (tos_ignore_flag) + ip_hdr->tos = 0; + else { + ip_hdr->tos = ip6_hdr->priority << 4; + ip_hdr->tos = ip_hdr->tos | (ip6_hdr->flow_lbl[0] >> 4); + } + + /* IPv4 Total Len = IPv6 Payload Len + + IPv4 Header Len (without options) - Options Headers Len */ + ip6_payload_len = ntohs(ip6_hdr->payload_len); + + if (ip6_payload_len == 0) + ntot_len = 0; + else + ntot_len = ip6_payload_len + IP4_IP6_HDR_DIFF - opts_len; + + ip_hdr->tot_len = htons(ntot_len); + + /* IPv4 TTL = IPv6 Hop Limit */ + ip_hdr->ttl = ip6_hdr->hop_limit; + + /* IPv4 Protocol = Next Header that will point to upper layer protocol */ + ip_hdr->protocol = next_hdr; + + /* IPv4 Src addr = last 4 bytes from IPv6 Src addr */ + ip_hdr->saddr = ip6_hdr->saddr.s6_addr32[3]; + /* IPv4 Dst addr = last 4 bytes from IPv6 Dst addr */ + ip_hdr->daddr = ip6_hdr->daddr.s6_addr32[3]; + + /* Calculate IPv4 header checksum */ + ip_hdr->check = 0; + ip_hdr->check = ip_fast_csum((unsigned char *)ip_hdr, ip_hdr->ihl); + + if (len_delta > 0) + { + /* PROCESS ICMP */ + + if (next_hdr == NEXTHDR_ICMP) + { + struct icmp6hdr *icmp6_hdr; + struct icmphdr *icmp_hdr; + + if ((len_delta -= sizeof(struct icmp6hdr)) >= 0) + { + icmp6_hdr = (struct icmp6hdr *)(src + sizeof(struct ipv6hdr) + opts_len); + icmp_hdr = (struct icmphdr *)(dst + sizeof(struct iphdr)); + + real_len += len_delta + sizeof(struct icmphdr); + + /* There is diffirent between ICMPv4/ICMPv6 protocol codes + IPPROTO_ICMP = 1 + IPPROTO_ICMPV6 = 58 */ + ip_hdr->protocol = IPPROTO_ICMP; + + if (include_flag) { + /* !!! Warnig !!! We discard ICMP packets with any ICMP as included + in ICMP Error. But ICMP Error messages can include ICMP Query message + */ + if (icmp6_hdr->icmp6_type != ICMPV6_ECHO_REQUEST) + { + PDEBUG("ip6_ip4(): included ICMPv6 in ICMPv6 Error message, packet dropped\n"); + return -1; + } + } + + /* Translate ICMPv6 to ICMPv4 */ + switch (icmp6_hdr->icmp6_type) + { +/* ICMP Error messages */ + /* Destination Unreachable (Type 1) */ + case ICMPV6_DEST_UNREACH: /* Type 1 */ + icmp_hdr->type = ICMP_DEST_UNREACH; /* to Type 3 */ + icmp_hdr->un.echo.id = 0; + icmp_hdr->un.echo.sequence = 0; + switch (icmp6_hdr->icmp6_code) + { + case ICMPV6_NOROUTE: /* Code 0 */ + case ICMPV6_NOT_NEIGHBOUR: /* Code 2 */ + case ICMPV6_ADDR_UNREACH: /* Code 3 */ + icmp_hdr->code = ICMP_HOST_UNREACH; /* To Code 1 */ + break; + case ICMPV6_ADM_PROHIBITED: /* Code 1 */ + icmp_hdr->code = ICMP_HOST_ANO; /* To Code 10 */ + break; + case ICMPV6_PORT_UNREACH: /* Code 4 */ + icmp_hdr->code = ICMP_PORT_UNREACH; /* To Code 3 */ + + break; + default: /* discard any other codes */ + PDEBUG("ip6_ip4(): Unknown ICMPv6 Type %d Code %d - packet dropped.\n", + ICMPV6_DEST_UNREACH, icmp6_hdr->icmp6_code); + return -1; + } + break; + /* Packet Too Big (Type 2) */ + case ICMPV6_PKT_TOOBIG: /* Type 2 */ + icmp_hdr->type = ICMP_DEST_UNREACH; /* to Type 3 */ + icmp_hdr->code = ICMP_FRAG_NEEDED; /* to Code 4 */ + /* Change MTU, RFC 2765 (SIIT), 4.2: + The MTU field needs to be adjusted for the difference between + the IPv4 and IPv6 header sizes taking into account whether or + not the packet in error includes a Fragment header. + */ + /* !!! Don't implement !!! */ + icmp_hdr->un.frag.mtu = (__u16) icmp6_hdr->icmp6_mtu; + break; + /* Time Exceeded (Type 3) */ + case ICMPV6_TIME_EXCEED: + icmp_hdr->type = ICMP_TIME_EXCEEDED; /* to Type 11 */ + icmp_hdr->code = icmp6_hdr->icmp6_code; /* Code unchanged */ + break; + /* Parameter Problem (Type 4) */ + case ICMPV6_PARAMPROB: + switch (icmp6_hdr->icmp6_code) { + case ICMPV6_UNK_NEXTHDR: /* Code 1 */ + icmp_hdr->type = ICMP_DEST_UNREACH; /* to Type 3 */ + icmp_hdr->code = ICMP_PROT_UNREACH; /* to Code 2 */ + break; + default: /* if Code != 1 */ + icmp_hdr->type = ICMP_PARAMETERPROB; /* to Type 12 */ + icmp_hdr->code = 0; /* to Code 0 */ + /* Update Pointer field + RFC 2765 (SIIT), 4.2: + The Pointer needs to be updated to point to the corresponding + field in the translated include IP header. + */ + switch (ntohl(icmp6_hdr->icmp6_pointer)) + { + case 0: /* IPv6 Version -> IPv4 Version */ + icmp_hdr->un.echo.id = 0; + break; + case 4: /* IPv6 PayloadLength -> IPv4 Total Length */ + icmp_hdr->un.echo.id = 0x0002; /* 2 */ + break; + case 6: /* IPv6 Next Header-> IPv4 Protocol */ + icmp_hdr->un.echo.id = 0x0009; /* 9 */ + break; + case 7: /* IPv6 Hop Limit -> IPv4 TTL */ + icmp_hdr->un.echo.id = 0x0008; /* 8 */ + break; + case 8: /* IPv6 Src addr -> IPv4 Src addr */ + icmp_hdr->un.echo.id = 0x000c; /* 12 */ + break; + case 24: /* IPv6 Dst addr -> IPv4 Dst addr*/ + icmp_hdr->un.echo.id = 0x0010; /* 16 */ + break; + default: /* set all ones in other cases */ + icmp_hdr->un.echo.id = 0xff; + break; + } + break; + } + break; + +/* End of ICMP Error messages */ + + /* Echo Request and Echo Reply (Type 128 and 129) */ + case ICMPV6_ECHO_REQUEST: + icmperr = 0; /* not error ICMP message */ + icmp_hdr->type = ICMP_ECHO; /* to Type 8 */ + icmp_hdr->code = 0; /* to Code 0 */ + icmp_hdr->un.echo.id = icmp6_hdr->icmp6_identifier; + icmp_hdr->un.echo.sequence = icmp6_hdr->icmp6_sequence; + /* copy rest of ICMP data to result packet */ + if (len_delta > 0) + memcpy(((char *)icmp_hdr) + sizeof(struct icmphdr), + ((char *)icmp6_hdr) + sizeof(struct icmp6hdr), len_delta); + break; + case ICMPV6_ECHO_REPLY: + icmperr = 0; /* not error ICMP message */ + icmp_hdr->type = ICMP_ECHOREPLY; /* to Type 0 */ + icmp_hdr->code = 0; /* to Code 0 */ + icmp_hdr->un.echo.id = icmp6_hdr->icmp6_identifier; + icmp_hdr->un.echo.sequence = icmp6_hdr->icmp6_sequence; + /* copy rest of ICMP data */ + if (len_delta > 0) + memcpy(((char *)icmp_hdr) + sizeof(struct icmphdr), + ((char *)icmp6_hdr) + sizeof(struct icmp6hdr), len_delta); + break; + default: + /* Unknown error messages. Silently drop. */ + PDEBUG("ip6_ip4(): unknown ICMPv6 Type %d, packet dropped.\n", icmp6_hdr->icmp6_type); + return -1; + } + + if (icmperr) + { + /* If ICMP Error message, we translate IP included packet*/ + if (len_delta >= sizeof(struct ipv6hdr)) + { + if((inc_opts_len = ip6_ip4((char *)icmp6_hdr + sizeof(struct icmp6hdr), len_delta, + (char *)icmp_hdr + sizeof(struct icmphdr), 1)) == -1) { + PDEBUG("ip6_ip4(): incorrect translation of ICMPv6 Error message, packet dropped\n"); + return -1; + } + /* correct IPv4 Total Len that = old Total Len + - Options Headers Len in included IP packet + - diffirence between IPv6 Header Len and IPv4 Header Len + */ + if (ntot_len != 0) + ip_hdr->tot_len = htons(ntot_len - inc_opts_len - IP4_IP6_HDR_DIFF); + real_len = real_len - inc_opts_len - IP4_IP6_HDR_DIFF; + } + else if (len_delta > 0) + { + /* May be it need set 0x0 to rest area in result IPv4 packet, + * but we copy rest data unchanged + */ + memcpy(((char *)icmp_hdr) + sizeof(struct icmphdr), + ((char *)icmp6_hdr) + sizeof(struct icmp6hdr), len_delta); + } + } + + /* Calculate IPv4 Header checksum */ + ip_hdr->check = 0; + ip_hdr->check = ip_fast_csum((unsigned char *)ip_hdr, ip_hdr->ihl); + + /* Calculate ICMPv4 checksum */ + if (ntot_len != 0) + { + icmp_hdr->checksum = 0; + icmp_hdr->checksum = ip_compute_csum((unsigned char *)icmp_hdr, ntohs(ip_hdr->tot_len) + - sizeof(struct iphdr)); + } + } + else + { + PDEBUG("ip6_ip4(): error length ICMP packet, packet dropped.\n"); + return -1; + } + + } + /* PROCESS TCP and UDP (and rest data) */ + + else { + real_len += len_delta; + /* we copy rest data to IPv4 packet without changing */ + memcpy(dst+sizeof(struct iphdr), src + sizeof(struct ipv6hdr) + opts_len, len_delta); + } + } + + if (include_flag) /* if it's included IP packet */ + return opts_len; /* return options headers length */ + else + return real_len; /* result packet len */ +} + +/* + * ip4_fragment(skb, len, hdr_len, dev, eth_h) + * to fragment original IPv4 packet if result IPv6 packet will be > 1280 + */ + +static int ip4_fragment(struct sk_buff *skb, int len, int hdr_len, struct net_device *dev, struct ethhdr *eth_h) +{ + struct sk_buff *skb2 = NULL; /* pointer to new struct sk_buff for transleded packet */ + char buff[FRAG_BUFF_SIZE+hdr_len]; /* buffer to form new fragment packet */ + char *cur_ptr = skb->data+hdr_len; /* pointter to current packet data with len = frag_len */ + struct iphdr *ih4 = (struct iphdr *) skb->data; + struct iphdr *new_ih4 = (struct iphdr *) buff; /* point to new IPv4 hdr */ + struct ethhdr *new_eth_h; /* point to ether hdr, need to set hard header data in fragment */ + int data_len = len - hdr_len; /* origin packet data len */ + int rest_len = data_len; /* rest data to fragment */ + int frag_len = 0; /* current fragment len */ + int last_frag = 0; /* last fragment flag, if = 1, it's last fragment */ + int flag_last_mf = 0; + __u16 new_id = 0; /* to generate identification field */ + __u16 frag_offset = 0; /* fragment offset */ + unsigned int csum; + unsigned short udp_len; + +#ifdef SIIT_DEBUG + printk("siit: it's DF == 0 and result IPv6 packet will be > 1280\n"); + siit_print_dump(skb->data, hdr_len, "siit: (orig) ipv4_hdr dump"); +#endif + + if ((ntohs(ih4->frag_off) & IP_MF) == 0 ) + /* it's a case we'll clear MF flag in our last packet */ + flag_last_mf = 1; + + if (ih4->protocol == IPPROTO_UDP) { + if ( (ntohs(ih4->frag_off) & IP_OFFSET) == 0) { + struct udphdr *udp_hdr = (struct udphdr *)((char *)ih4 + hdr_len); + if (!flag_last_mf) { + if (udp_hdr->check == 0) { + /* it's a first fragment with ZERO checksum and we drop packet */ + printk("siit: First fragment of UDP with zero checksum - packet droped\n"); + printk("siit: addr: %x src port: %d dst port: %d\n", + htonl(ih4->saddr), htons(udp_hdr->source), htons(udp_hdr->dest)); + return -1; + } + } + else if (udp_hdr->check == 0) { + /* Calculate UDP checksum only if it's not fragment */ + udp_len = ntohs(udp_hdr->len); + csum = 0; + csum = csum_partial((unsigned char *)udp_hdr, udp_len, csum); + udp_hdr->check = csum_tcpudp_magic(ih4->saddr, ih4->daddr, udp_len, IPPROTO_UDP, csum); + } + } + } + + frag_offset = ntohs(ih4->frag_off) & IP_OFFSET; + + new_id = ih4->id; + + while(1) { + if (rest_len <= FRAG_BUFF_SIZE) { + /* it's last fragmen */ + frag_len = rest_len; /* rest data */ + last_frag = 1; + } + else + frag_len = FRAG_BUFF_SIZE; + + /* copy IP header to buffer */ + memcpy(buff, skb->data, hdr_len); + /* copy data to buffer with len = frag_len */ + memcpy(buff + hdr_len, cur_ptr, frag_len); + + /* set id field in new IPv4 header*/ + new_ih4->id = new_id; + + /* is it last fragmet */ + if(last_frag && flag_last_mf) + /* clear MF flag */ + new_ih4->frag_off = htons(frag_offset & (~IP_MF)); + else + /* set MF flag */ + new_ih4->frag_off = htons(frag_offset | IP_MF); + + /* change packet total length */ + new_ih4->tot_len = htons(frag_len+hdr_len); + + /* rebuild the header checksum (IP needs it) */ + new_ih4->check = 0; + new_ih4->check = ip_fast_csum((unsigned char *)new_ih4,new_ih4->ihl); + + /* Allocate new sk_buff to compose translated packet */ + skb2 = dev_alloc_skb(frag_len+hdr_len+dev->hard_header_len+IP4_IP6_HDR_DIFF+IP6_FRAGMENT_SIZE); + if (!skb2) { + printk(KERN_DEBUG "%s: alloc_skb failure - packet dropped.\n", dev->name); + dev_kfree_skb(skb2); + return -1; + } + /* allocate skb->data portion for IP header len, fragment data len and ether header len + * and copy to head ether header from origin skb + */ + memcpy(skb_put(skb2, frag_len+hdr_len+dev->hard_header_len+IP4_IP6_HDR_DIFF+IP6_FRAGMENT_SIZE), (char *) eth_h, + dev->hard_header_len); + /* correct ether header data, ether protocol field to ETH_P_IPV6 */ + new_eth_h = (struct ethhdr *)skb2->data; + new_eth_h->h_proto = htons(ETH_P_IPV6); + + /* reset the mac header */ + skb_reset_mac_header(skb2); + + /* pull ether header from new skb->data */ + skb_pull(skb2, dev->hard_header_len); + /* set skb protocol to IPV6 */ + skb2->protocol = htons(ETH_P_IPV6); + + /* call translation function */ + if ( ip4_ip6(buff, frag_len+hdr_len, skb2->data, 0) == -1) { + dev_kfree_skb(skb2); + return -1; + } + + /* + * Set needed fields in new sk_buff + */ + skb2->dev = dev; + skb2->ip_summed = CHECKSUM_UNNECESSARY; + skb2->pkt_type = PACKET_HOST; + + /* Add transmit statistic */ + siit_stats(dev)->tx_packets++; + siit_stats(dev)->tx_bytes += skb2->len; + + /* send packet to upper layer */ + netif_rx(skb2); + + /* exit if it was last fragment */ + if (last_frag) + break; + + /* correct current data pointer */ + cur_ptr += frag_len; + /* rest data len */ + rest_len -= frag_len; + /* current fragment offset */ + frag_offset = (frag_offset*8 + frag_len)/8; + } + + return 0; +} +/* + * Transmit a packet (called by the kernel) + * + * siit_xmit(skb, dev) + * + * where + * skb - pointer to struct sk_buff with incomed packet + * dev - pointer to struct device on which packet revieved + * + * Statistic: + * for all incoming packes: + * stats.rx_bytes+=skb->len + * stats.rx_packets++ + * for packets we can't transle: + * stats.tx_errors++ + * device busy: + * stats.tx_errors++ + * for packets we can't allocate sk_buff: + * stats.tx_dropped++ + * for outgoing packes: + * stats.tx_packets++ + * stats.tx_bytes+=skb2->len !!! But we don't set skb2->len !!! + */ + +static int siit_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct sk_buff *skb2 = NULL;/* pointer to new struct sk_buff for transleded packet */ + struct ethhdr *eth_h; /* pointer to incoming Ether header */ + int len; /* original packets length */ + int new_packet_len; + int skb_delta = 0; /* delta size for allocate new skb */ + char new_packet_buff[2048]; + + /* Check pointer to sk_buff and device structs */ + if (skb == NULL || dev == NULL) + return -EINVAL; + + /* Add receive statistic */ + siit_stats(dev)->rx_bytes += skb->len; + siit_stats(dev)->rx_packets++; + + dev->trans_start = jiffies; + + /* Upper layer (IP) protocol forms sk_buff for outgoing packet + * and sets IP header + Ether header too. IP layer sets outgoing + * device in sk_buff->dev. + * In function (from linux/net/core/dev.c) ther is a call to + * device transmit function (dev->hard_start_xmit): + * + * dev_queue_xmit(struct sk_buff *skb) + * { + * ... + * device *dev = skb->dev; + * ... + * dev->hard_start_xmit(skb, dev); + * ... + * } + * We save pointer to ether header in eth_h and skb_pull ether header + * from data field of skb_buff + */ + + eth_h = (struct ethhdr *)skb->data; /* point to incoming packet Ether Header */ + +#ifdef SIIT_DEBUG + siit_print_dump(skb->data, ETH_HLEN, "siit: eth_hdr dump"); +#endif + + /* Remove hardware header from origin sk_buff */ + skb_pull(skb,dev->hard_header_len); + + /* + * Process IPv4 paket + */ + if (ntohs(skb->protocol) == ETH_P_IP) { + int hdr_len; /* IPv4 header length */ + int data_len; /* IPv4 data length */ + struct iphdr *ih4; /* pointer to IPv4 header */ + struct icmphdr *icmp_hdr; /* point to current ICMPv4 header struct */ + + ih4 = (struct iphdr *)skb->data; /* point to incoming packet's IPv4 header */ + + /* Check IPv4 Total Length */ + if (skb->len != ntohs(ih4->tot_len)) { + PDEBUG("siit_xmit(): Different skb_len %x and ip4 tot_len %x - packet dropped.\n", + skb->len, ih4->tot_len); + siit_stats(dev)->tx_errors++; + dev_kfree_skb(skb); + return 0; + } + + len = skb->len; /* packet's total len */ + hdr_len = (int)(ih4->ihl * 4); /* packet's header len */ + data_len = len - hdr_len; /* packet's data len */ + + /* If DF == 0 */ + if ( (ntohs(ih4->frag_off) & IP_DF) == 0 ) { + /* If result IPv6 packet will be > 1280 + we need to fragment original IPv4 packet + */ + if ( data_len > FRAG_BUFF_SIZE ) { + /* call function that fragment packet and translate to IPv6 each fragment + * and send to upper layer + */ + if ( ip4_fragment(skb, len, hdr_len, dev, eth_h) == -1) { + siit_stats(dev)->tx_errors++; + } + /* Free incoming skb */ + dev_kfree_skb(skb); + /* Device can accept a new packet */ + + return 0; + + } + } + /* If DF == 1 && MF == 0 && Fragment Offset == 0 + * we don't include fragment header + */ + if ( ntohs(ih4->frag_off) == IP_DF ) + skb_delta = IP4_IP6_HDR_DIFF; /* delta is +20 */ + else + skb_delta = IP4_IP6_HDR_DIFF + IP6_FRAGMENT_SIZE; /* delta is +20 and +8 */ + + /* If it's ICMP, check is it included IP packet in it */ + if ( ih4->protocol == IPPROTO_ICMP) { + icmp_hdr = (struct icmphdr *) (skb->data+hdr_len); /* point to ICMPv4 header */ + if ( icmp_hdr->type != ICMP_ECHO && icmp_hdr->type != ICMP_ECHOREPLY) { + /* + * It's ICMP Error that has included IP packet + * we'll add only +20 because we don't include Fragment Header + * into translated included IP packet + */ + skb_delta += IP4_IP6_HDR_DIFF; + } + } + + /* Allocate new sk_buff to compose translated packet */ + skb2 = dev_alloc_skb(len+dev->hard_header_len+skb_delta); + if (!skb2) { + printk(KERN_DEBUG "%s: alloc_skb failure - packet dropped.\n", dev->name); + dev_kfree_skb(skb); + siit_stats(dev)->rx_dropped++; + + return 0; + } + /* allocate skb->data portion = IPv4 packet len + ether header len + * + skb_delta (max = two times (diffirence between IPv4 header and + * IPv6 header + Frag Header), second for included packet, + * and copy to head of skb->data ether header from origin skb + */ + memcpy(skb_put(skb2, len+dev->hard_header_len+skb_delta), (char *)eth_h, dev->hard_header_len); + /* correct ether header data, ether protocol field to ETH_P_IPV6 */ + eth_h = (struct ethhdr *)skb2->data; + eth_h->h_proto = htons(ETH_P_IPV6); + skb_reset_mac_header(skb2); + /* remove ether header from new skb->data, + * NOTE! data will rest, pointer to data and data len will change + */ + skb_pull(skb2,dev->hard_header_len); + /* set skb protocol to IPV6 */ + skb2->protocol = htons(ETH_P_IPV6); + + /* call translation function */ + if (ip4_ip6(skb->data, len, skb2->data, 0) == -1 ) { + dev_kfree_skb(skb); + dev_kfree_skb(skb2); + siit_stats(dev)->rx_errors++; + + return 0; + } + } + /* + * IPv6 paket + */ + else if (ntohs(skb->protocol) == ETH_P_IPV6) { + +#ifdef SIIT_DEBUG + siit_print_dump(skb->data, sizeof(struct ipv6hdr), "siit: (in) ip6_hdr dump"); +#endif + /* packet len = skb->data len*/ + len = skb->len; + + /* call translation function */ + if ((new_packet_len = ip6_ip4(skb->data, len, new_packet_buff, 0)) == -1 ) + { + PDEBUG("siit_xmit(): error translation ipv6->ipv4, packet dropped.\n"); + siit_stats(dev)->rx_dropped++; + goto end; + } + + /* Allocate new sk_buff to compose translated packet */ + skb2 = dev_alloc_skb(new_packet_len + dev->hard_header_len); + if (!skb2) { + printk(KERN_DEBUG "%s: alloc_skb failure, packet dropped.\n", dev->name); + siit_stats(dev)->rx_dropped++; + goto end; + } + memcpy(skb_put(skb2, new_packet_len + dev->hard_header_len), (char *)eth_h, dev->hard_header_len); + eth_h = (struct ethhdr *)skb2->data; + eth_h->h_proto = htons(ETH_P_IP); + skb_reset_mac_header(skb2); + skb_pull(skb2, dev->hard_header_len); + memcpy(skb2->data, new_packet_buff, new_packet_len); + skb2->protocol = htons(ETH_P_IP); + } + else { + PDEBUG("siit_xmit(): unsupported protocol family %x, packet dropped.\n", skb->protocol); + goto end; + } + + /* + * Set needed fields in new sk_buff + */ + skb2->pkt_type = PACKET_HOST; + skb2->dev = dev; + skb2->ip_summed = CHECKSUM_UNNECESSARY; + + /* Add transmit statistic */ + siit_stats(dev)->tx_packets++; + siit_stats(dev)->tx_bytes += skb2->len; + + /* Send packet to upper layer protocol */ + netif_rx(skb2); + +end: + dev_kfree_skb(skb); + + return 0; +} + +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) +static bool header_ops_init = false; +static struct header_ops siit_header_ops ____cacheline_aligned; +#endif + +#if !(defined CONFIG_COMPAT_NET_DEV_OPS) && LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,30) +static const struct net_device_ops siit_netdev_ops = { + .ndo_open = siit_open, + .ndo_stop = siit_release, + .ndo_start_xmit = siit_xmit, +}; +#endif + +/* + * The init function initialize of the SIIT device.. + * It is invoked by register_netdev() + */ + +static void +siit_init(struct net_device *dev) +{ + ether_setup(dev); /* assign some of the fields */ + random_ether_addr(dev->dev_addr); + + /* + * Assign device function. + */ +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30) + dev->open = siit_open; + dev->stop = siit_release; + dev->hard_start_xmit = siit_xmit; +#else +#if !(defined CONFIG_COMPAT_NET_DEV_OPS) && LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,30) + dev->netdev_ops = &siit_netdev_ops; +#endif +#endif + dev->flags |= IFF_NOARP; /* ARP not used */ + dev->tx_queue_len = 10; + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + dev->hard_header_cache = NULL; /* Disable caching */ + memset(netdev_priv(dev), 0, sizeof(struct net_device_stats)); + dev->get_stats = siit_get_stats; +#else + if (!header_ops_init) { + memcpy(&siit_header_ops, dev->header_ops, sizeof(struct header_ops)); + siit_header_ops.cache = NULL; + } + dev->header_ops = &siit_header_ops; +#endif +} + +/* + * Finally, the module stuff + */ +static struct net_device *siit_dev = NULL; + +int init_module(void) +{ + int res = -ENOMEM; + int priv_size; + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + priv_size = sizeof(struct net_device_stats); +#else + priv_size = sizeof(struct header_ops); +#endif + siit_dev = alloc_netdev(priv_size, "siit%d", siit_init); + if (!siit_dev) + goto err_alloc; + + res = register_netdev(siit_dev); + if (res) + goto err_register; + + return 0; + +err_register: + free_netdev(siit_dev); +err_alloc: + printk(KERN_ERR "Error creating siit device: %d\n", res); + return res; +} + +void cleanup_module(void) +{ + unregister_netdev(siit_dev); + free_netdev(siit_dev); +} + + |