| /* |
| * INET An implementation of the TCP/IP protocol suite for the LINUX |
| * operating system. INET is implemented using the BSD Socket |
| * interface as the means of communication with the user level. |
| * |
| * The options processing module for ip.c |
| * |
| * Authors: A.N.Kuznetsov |
| * |
| */ |
| |
| #include <linux/capability.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/types.h> |
| #include <asm/uaccess.h> |
| #include <asm/unaligned.h> |
| #include <linux/skbuff.h> |
| #include <linux/ip.h> |
| #include <linux/icmp.h> |
| #include <linux/netdevice.h> |
| #include <linux/rtnetlink.h> |
| #include <net/sock.h> |
| #include <net/ip.h> |
| #include <net/icmp.h> |
| #include <net/route.h> |
| #include <net/cipso_ipv4.h> |
| |
| /* |
| * Write options to IP header, record destination address to |
| * source route option, address of outgoing interface |
| * (we should already know it, so that this function is allowed be |
| * called only after routing decision) and timestamp, |
| * if we originate this datagram. |
| * |
| * daddr is real destination address, next hop is recorded in IP header. |
| * saddr is address of outgoing interface. |
| */ |
| |
| void ip_options_build(struct sk_buff *skb, struct ip_options *opt, |
| __be32 daddr, struct rtable *rt, int is_frag) |
| { |
| unsigned char *iph = skb_network_header(skb); |
| |
| memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options)); |
| memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen); |
| opt = &(IPCB(skb)->opt); |
| |
| if (opt->srr) |
| memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4); |
| |
| if (!is_frag) { |
| if (opt->rr_needaddr) |
| ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, skb, rt); |
| if (opt->ts_needaddr) |
| ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, skb, rt); |
| if (opt->ts_needtime) { |
| struct timespec tv; |
| __be32 midtime; |
| getnstimeofday(&tv); |
| midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC); |
| memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4); |
| } |
| return; |
| } |
| if (opt->rr) { |
| memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]); |
| opt->rr = 0; |
| opt->rr_needaddr = 0; |
| } |
| if (opt->ts) { |
| memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]); |
| opt->ts = 0; |
| opt->ts_needaddr = opt->ts_needtime = 0; |
| } |
| } |
| |
| /* |
| * Provided (sopt, skb) points to received options, |
| * build in dopt compiled option set appropriate for answering. |
| * i.e. invert SRR option, copy anothers, |
| * and grab room in RR/TS options. |
| * |
| * NOTE: dopt cannot point to skb. |
| */ |
| |
| int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb) |
| { |
| const struct ip_options *sopt; |
| unsigned char *sptr, *dptr; |
| int soffset, doffset; |
| int optlen; |
| __be32 daddr; |
| |
| memset(dopt, 0, sizeof(struct ip_options)); |
| |
| sopt = &(IPCB(skb)->opt); |
| |
| if (sopt->optlen == 0) |
| return 0; |
| |
| sptr = skb_network_header(skb); |
| dptr = dopt->__data; |
| |
| daddr = skb_rtable(skb)->rt_spec_dst; |
| |
| if (sopt->rr) { |
| optlen = sptr[sopt->rr+1]; |
| soffset = sptr[sopt->rr+2]; |
| dopt->rr = dopt->optlen + sizeof(struct iphdr); |
| memcpy(dptr, sptr+sopt->rr, optlen); |
| if (sopt->rr_needaddr && soffset <= optlen) { |
| if (soffset + 3 > optlen) |
| return -EINVAL; |
| dptr[2] = soffset + 4; |
| dopt->rr_needaddr = 1; |
| } |
| dptr += optlen; |
| dopt->optlen += optlen; |
| } |
| if (sopt->ts) { |
| optlen = sptr[sopt->ts+1]; |
| soffset = sptr[sopt->ts+2]; |
| dopt->ts = dopt->optlen + sizeof(struct iphdr); |
| memcpy(dptr, sptr+sopt->ts, optlen); |
| if (soffset <= optlen) { |
| if (sopt->ts_needaddr) { |
| if (soffset + 3 > optlen) |
| return -EINVAL; |
| dopt->ts_needaddr = 1; |
| soffset += 4; |
| } |
| if (sopt->ts_needtime) { |
| if (soffset + 3 > optlen) |
| return -EINVAL; |
| if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) { |
| dopt->ts_needtime = 1; |
| soffset += 4; |
| } else { |
| dopt->ts_needtime = 0; |
| |
| if (soffset + 7 <= optlen) { |
| __be32 addr; |
| |
| memcpy(&addr, dptr+soffset-1, 4); |
| if (inet_addr_type(dev_net(skb_dst(skb)->dev), addr) != RTN_UNICAST) { |
| dopt->ts_needtime = 1; |
| soffset += 8; |
| } |
| } |
| } |
| } |
| dptr[2] = soffset; |
| } |
| dptr += optlen; |
| dopt->optlen += optlen; |
| } |
| if (sopt->srr) { |
| unsigned char *start = sptr+sopt->srr; |
| __be32 faddr; |
| |
| optlen = start[1]; |
| soffset = start[2]; |
| doffset = 0; |
| if (soffset > optlen) |
| soffset = optlen + 1; |
| soffset -= 4; |
| if (soffset > 3) { |
| memcpy(&faddr, &start[soffset-1], 4); |
| for (soffset-=4, doffset=4; soffset > 3; soffset-=4, doffset+=4) |
| memcpy(&dptr[doffset-1], &start[soffset-1], 4); |
| /* |
| * RFC1812 requires to fix illegal source routes. |
| */ |
| if (memcmp(&ip_hdr(skb)->saddr, |
| &start[soffset + 3], 4) == 0) |
| doffset -= 4; |
| } |
| if (doffset > 3) { |
| memcpy(&start[doffset-1], &daddr, 4); |
| dopt->faddr = faddr; |
| dptr[0] = start[0]; |
| dptr[1] = doffset+3; |
| dptr[2] = 4; |
| dptr += doffset+3; |
| dopt->srr = dopt->optlen + sizeof(struct iphdr); |
| dopt->optlen += doffset+3; |
| dopt->is_strictroute = sopt->is_strictroute; |
| } |
| } |
| if (sopt->cipso) { |
| optlen = sptr[sopt->cipso+1]; |
| dopt->cipso = dopt->optlen+sizeof(struct iphdr); |
| memcpy(dptr, sptr+sopt->cipso, optlen); |
| dptr += optlen; |
| dopt->optlen += optlen; |
| } |
| while (dopt->optlen & 3) { |
| *dptr++ = IPOPT_END; |
| dopt->optlen++; |
| } |
| return 0; |
| } |
| |
| /* |
| * Options "fragmenting", just fill options not |
| * allowed in fragments with NOOPs. |
| * Simple and stupid 8), but the most efficient way. |
| */ |
| |
| void ip_options_fragment(struct sk_buff * skb) |
| { |
| unsigned char *optptr = skb_network_header(skb) + sizeof(struct iphdr); |
| struct ip_options * opt = &(IPCB(skb)->opt); |
| int l = opt->optlen; |
| int optlen; |
| |
| while (l > 0) { |
| switch (*optptr) { |
| case IPOPT_END: |
| return; |
| case IPOPT_NOOP: |
| l--; |
| optptr++; |
| continue; |
| } |
| optlen = optptr[1]; |
| if (optlen<2 || optlen>l) |
| return; |
| if (!IPOPT_COPIED(*optptr)) |
| memset(optptr, IPOPT_NOOP, optlen); |
| l -= optlen; |
| optptr += optlen; |
| } |
| opt->ts = 0; |
| opt->rr = 0; |
| opt->rr_needaddr = 0; |
| opt->ts_needaddr = 0; |
| opt->ts_needtime = 0; |
| } |
| |
| /* |
| * Verify options and fill pointers in struct options. |
| * Caller should clear *opt, and set opt->data. |
| * If opt == NULL, then skb->data should point to IP header. |
| */ |
| |
| int ip_options_compile(struct net *net, |
| struct ip_options * opt, struct sk_buff * skb) |
| { |
| int l; |
| unsigned char * iph; |
| unsigned char * optptr; |
| int optlen; |
| unsigned char * pp_ptr = NULL; |
| struct rtable *rt = NULL; |
| |
| if (skb != NULL) { |
| rt = skb_rtable(skb); |
| optptr = (unsigned char *)&(ip_hdr(skb)[1]); |
| } else |
| optptr = opt->__data; |
| iph = optptr - sizeof(struct iphdr); |
| |
| for (l = opt->optlen; l > 0; ) { |
| switch (*optptr) { |
| case IPOPT_END: |
| for (optptr++, l--; l>0; optptr++, l--) { |
| if (*optptr != IPOPT_END) { |
| *optptr = IPOPT_END; |
| opt->is_changed = 1; |
| } |
| } |
| goto eol; |
| case IPOPT_NOOP: |
| l--; |
| optptr++; |
| continue; |
| } |
| optlen = optptr[1]; |
| if (optlen<2 || optlen>l) { |
| pp_ptr = optptr; |
| goto error; |
| } |
| switch (*optptr) { |
| case IPOPT_SSRR: |
| case IPOPT_LSRR: |
| if (optlen < 3) { |
| pp_ptr = optptr + 1; |
| goto error; |
| } |
| if (optptr[2] < 4) { |
| pp_ptr = optptr + 2; |
| goto error; |
| } |
| /* NB: cf RFC-1812 5.2.4.1 */ |
| if (opt->srr) { |
| pp_ptr = optptr; |
| goto error; |
| } |
| if (!skb) { |
| if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) { |
| pp_ptr = optptr + 1; |
| goto error; |
| } |
| memcpy(&opt->faddr, &optptr[3], 4); |
| if (optlen > 7) |
| memmove(&optptr[3], &optptr[7], optlen-7); |
| } |
| opt->is_strictroute = (optptr[0] == IPOPT_SSRR); |
| opt->srr = optptr - iph; |
| break; |
| case IPOPT_RR: |
| if (opt->rr) { |
| pp_ptr = optptr; |
| goto error; |
| } |
| if (optlen < 3) { |
| pp_ptr = optptr + 1; |
| goto error; |
| } |
| if (optptr[2] < 4) { |
| pp_ptr = optptr + 2; |
| goto error; |
| } |
| if (optptr[2] <= optlen) { |
| if (optptr[2]+3 > optlen) { |
| pp_ptr = optptr + 2; |
| goto error; |
| } |
| if (rt) { |
| memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4); |
| opt->is_changed = 1; |
| } |
| optptr[2] += 4; |
| opt->rr_needaddr = 1; |
| } |
| opt->rr = optptr - iph; |
| break; |
| case IPOPT_TIMESTAMP: |
| if (opt->ts) { |
| pp_ptr = optptr; |
| goto error; |
| } |
| if (optlen < 4) { |
| pp_ptr = optptr + 1; |
| goto error; |
| } |
| if (optptr[2] < 5) { |
| pp_ptr = optptr + 2; |
| goto error; |
| } |
| if (optptr[2] <= optlen) { |
| unsigned char *timeptr = NULL; |
| if (optptr[2]+3 > optptr[1]) { |
| pp_ptr = optptr + 2; |
| goto error; |
| } |
| switch (optptr[3]&0xF) { |
| case IPOPT_TS_TSONLY: |
| opt->ts = optptr - iph; |
| if (skb) |
| timeptr = &optptr[optptr[2]-1]; |
| opt->ts_needtime = 1; |
| optptr[2] += 4; |
| break; |
| case IPOPT_TS_TSANDADDR: |
| if (optptr[2]+7 > optptr[1]) { |
| pp_ptr = optptr + 2; |
| goto error; |
| } |
| opt->ts = optptr - iph; |
| if (rt) { |
| memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4); |
| timeptr = &optptr[optptr[2]+3]; |
| } |
| opt->ts_needaddr = 1; |
| opt->ts_needtime = 1; |
| optptr[2] += 8; |
| break; |
| case IPOPT_TS_PRESPEC: |
| if (optptr[2]+7 > optptr[1]) { |
| pp_ptr = optptr + 2; |
| goto error; |
| } |
| opt->ts = optptr - iph; |
| { |
| __be32 addr; |
| memcpy(&addr, &optptr[optptr[2]-1], 4); |
| if (inet_addr_type(net, addr) == RTN_UNICAST) |
| break; |
| if (skb) |
| timeptr = &optptr[optptr[2]+3]; |
| } |
| opt->ts_needtime = 1; |
| optptr[2] += 8; |
| break; |
| default: |
| if (!skb && !capable(CAP_NET_RAW)) { |
| pp_ptr = optptr + 3; |
| goto error; |
| } |
| break; |
| } |
| if (timeptr) { |
| struct timespec tv; |
| u32 midtime; |
| getnstimeofday(&tv); |
| midtime = (tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC; |
| put_unaligned_be32(midtime, timeptr); |
| opt->is_changed = 1; |
| } |
| } else { |
| unsigned overflow = optptr[3]>>4; |
| if (overflow == 15) { |
| pp_ptr = optptr + 3; |
| goto error; |
| } |
| opt->ts = optptr - iph; |
| if (skb) { |
| optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4); |
| opt->is_changed = 1; |
| } |
| } |
| break; |
| case IPOPT_RA: |
| if (optlen < 4) { |
| pp_ptr = optptr + 1; |
| goto error; |
| } |
| if (optptr[2] == 0 && optptr[3] == 0) |
| opt->router_alert = optptr - iph; |
| break; |
| case IPOPT_CIPSO: |
| if ((!skb && !capable(CAP_NET_RAW)) || opt->cipso) { |
| pp_ptr = optptr; |
| goto error; |
| } |
| opt->cipso = optptr - iph; |
| if (cipso_v4_validate(skb, &optptr)) { |
| pp_ptr = optptr; |
| goto error; |
| } |
| break; |
| case IPOPT_SEC: |
| case IPOPT_SID: |
| default: |
| if (!skb && !capable(CAP_NET_RAW)) { |
| pp_ptr = optptr; |
| goto error; |
| } |
| break; |
| } |
| l -= optlen; |
| optptr += optlen; |
| } |
| |
| eol: |
| if (!pp_ptr) |
| return 0; |
| |
| error: |
| if (skb) { |
| icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24)); |
| } |
| return -EINVAL; |
| } |
| EXPORT_SYMBOL(ip_options_compile); |
| |
| /* |
| * Undo all the changes done by ip_options_compile(). |
| */ |
| |
| void ip_options_undo(struct ip_options * opt) |
| { |
| if (opt->srr) { |
| unsigned char * optptr = opt->__data+opt->srr-sizeof(struct iphdr); |
| memmove(optptr+7, optptr+3, optptr[1]-7); |
| memcpy(optptr+3, &opt->faddr, 4); |
| } |
| if (opt->rr_needaddr) { |
| unsigned char * optptr = opt->__data+opt->rr-sizeof(struct iphdr); |
| optptr[2] -= 4; |
| memset(&optptr[optptr[2]-1], 0, 4); |
| } |
| if (opt->ts) { |
| unsigned char * optptr = opt->__data+opt->ts-sizeof(struct iphdr); |
| if (opt->ts_needtime) { |
| optptr[2] -= 4; |
| memset(&optptr[optptr[2]-1], 0, 4); |
| if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC) |
| optptr[2] -= 4; |
| } |
| if (opt->ts_needaddr) { |
| optptr[2] -= 4; |
| memset(&optptr[optptr[2]-1], 0, 4); |
| } |
| } |
| } |
| |
| static struct ip_options_rcu *ip_options_get_alloc(const int optlen) |
| { |
| return kzalloc(sizeof(struct ip_options_rcu) + ((optlen + 3) & ~3), |
| GFP_KERNEL); |
| } |
| |
| static int ip_options_get_finish(struct net *net, struct ip_options_rcu **optp, |
| struct ip_options_rcu *opt, int optlen) |
| { |
| while (optlen & 3) |
| opt->opt.__data[optlen++] = IPOPT_END; |
| opt->opt.optlen = optlen; |
| if (optlen && ip_options_compile(net, &opt->opt, NULL)) { |
| kfree(opt); |
| return -EINVAL; |
| } |
| kfree(*optp); |
| *optp = opt; |
| return 0; |
| } |
| |
| int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp, |
| unsigned char __user *data, int optlen) |
| { |
| struct ip_options_rcu *opt = ip_options_get_alloc(optlen); |
| |
| if (!opt) |
| return -ENOMEM; |
| if (optlen && copy_from_user(opt->opt.__data, data, optlen)) { |
| kfree(opt); |
| return -EFAULT; |
| } |
| return ip_options_get_finish(net, optp, opt, optlen); |
| } |
| |
| int ip_options_get(struct net *net, struct ip_options_rcu **optp, |
| unsigned char *data, int optlen) |
| { |
| struct ip_options_rcu *opt = ip_options_get_alloc(optlen); |
| |
| if (!opt) |
| return -ENOMEM; |
| if (optlen) |
| memcpy(opt->opt.__data, data, optlen); |
| return ip_options_get_finish(net, optp, opt, optlen); |
| } |
| |
| void ip_forward_options(struct sk_buff *skb) |
| { |
| struct ip_options * opt = &(IPCB(skb)->opt); |
| unsigned char * optptr; |
| struct rtable *rt = skb_rtable(skb); |
| unsigned char *raw = skb_network_header(skb); |
| |
| if (opt->rr_needaddr) { |
| optptr = (unsigned char *)raw + opt->rr; |
| ip_rt_get_source(&optptr[optptr[2]-5], skb, rt); |
| opt->is_changed = 1; |
| } |
| if (opt->srr_is_hit) { |
| int srrptr, srrspace; |
| |
| optptr = raw + opt->srr; |
| |
| for ( srrptr=optptr[2], srrspace = optptr[1]; |
| srrptr <= srrspace; |
| srrptr += 4 |
| ) { |
| if (srrptr + 3 > srrspace) |
| break; |
| if (memcmp(&opt->nexthop, &optptr[srrptr-1], 4) == 0) |
| break; |
| } |
| if (srrptr + 3 <= srrspace) { |
| opt->is_changed = 1; |
| ip_hdr(skb)->daddr = opt->nexthop; |
| ip_rt_get_source(&optptr[srrptr-1], skb, rt); |
| optptr[2] = srrptr+4; |
| } else if (net_ratelimit()) |
| pr_crit("%s(): Argh! Destination lost!\n", __func__); |
| if (opt->ts_needaddr) { |
| optptr = raw + opt->ts; |
| ip_rt_get_source(&optptr[optptr[2]-9], skb, rt); |
| opt->is_changed = 1; |
| } |
| } |
| if (opt->is_changed) { |
| opt->is_changed = 0; |
| ip_send_check(ip_hdr(skb)); |
| } |
| } |
| |
| int ip_options_rcv_srr(struct sk_buff *skb) |
| { |
| struct ip_options *opt = &(IPCB(skb)->opt); |
| int srrspace, srrptr; |
| __be32 nexthop; |
| struct iphdr *iph = ip_hdr(skb); |
| unsigned char *optptr = skb_network_header(skb) + opt->srr; |
| struct rtable *rt = skb_rtable(skb); |
| struct rtable *rt2; |
| unsigned long orefdst; |
| int err; |
| |
| if (!rt) |
| return 0; |
| |
| if (skb->pkt_type != PACKET_HOST) |
| return -EINVAL; |
| if (rt->rt_type == RTN_UNICAST) { |
| if (!opt->is_strictroute) |
| return 0; |
| icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24)); |
| return -EINVAL; |
| } |
| if (rt->rt_type != RTN_LOCAL) |
| return -EINVAL; |
| |
| for (srrptr=optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) { |
| if (srrptr + 3 > srrspace) { |
| icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24)); |
| return -EINVAL; |
| } |
| memcpy(&nexthop, &optptr[srrptr-1], 4); |
| |
| orefdst = skb->_skb_refdst; |
| skb_dst_set(skb, NULL); |
| err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev); |
| rt2 = skb_rtable(skb); |
| if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) { |
| skb_dst_drop(skb); |
| skb->_skb_refdst = orefdst; |
| return -EINVAL; |
| } |
| refdst_drop(orefdst); |
| if (rt2->rt_type != RTN_LOCAL) |
| break; |
| /* Superfast 8) loopback forward */ |
| iph->daddr = nexthop; |
| opt->is_changed = 1; |
| } |
| if (srrptr <= srrspace) { |
| opt->srr_is_hit = 1; |
| opt->nexthop = nexthop; |
| opt->is_changed = 1; |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL(ip_options_rcv_srr); |