| #ifndef _IPV6_NF_REJECT_H |
| #define _IPV6_NF_REJECT_H |
| |
| #include <net/ipv6.h> |
| #include <net/ip6_route.h> |
| #include <net/ip6_fib.h> |
| #include <net/ip6_checksum.h> |
| #include <linux/netfilter_ipv6.h> |
| |
| static inline void |
| nf_send_unreach6(struct net *net, struct sk_buff *skb_in, unsigned char code, |
| unsigned int hooknum) |
| { |
| if (hooknum == NF_INET_LOCAL_OUT && skb_in->dev == NULL) |
| skb_in->dev = net->loopback_dev; |
| |
| icmpv6_send(skb_in, ICMPV6_DEST_UNREACH, code, 0); |
| } |
| |
| /* Send RST reply */ |
| static void nf_send_reset6(struct net *net, struct sk_buff *oldskb, int hook) |
| { |
| struct sk_buff *nskb; |
| struct tcphdr otcph, *tcph; |
| unsigned int otcplen, hh_len; |
| int tcphoff, needs_ack; |
| const struct ipv6hdr *oip6h = ipv6_hdr(oldskb); |
| struct ipv6hdr *ip6h; |
| #define DEFAULT_TOS_VALUE 0x0U |
| const __u8 tclass = DEFAULT_TOS_VALUE; |
| struct dst_entry *dst = NULL; |
| u8 proto; |
| __be16 frag_off; |
| struct flowi6 fl6; |
| |
| if ((!(ipv6_addr_type(&oip6h->saddr) & IPV6_ADDR_UNICAST)) || |
| (!(ipv6_addr_type(&oip6h->daddr) & IPV6_ADDR_UNICAST))) { |
| pr_debug("addr is not unicast.\n"); |
| return; |
| } |
| |
| proto = oip6h->nexthdr; |
| tcphoff = ipv6_skip_exthdr(oldskb, ((u8*)(oip6h+1) - oldskb->data), &proto, &frag_off); |
| |
| if ((tcphoff < 0) || (tcphoff > oldskb->len)) { |
| pr_debug("Cannot get TCP header.\n"); |
| return; |
| } |
| |
| otcplen = oldskb->len - tcphoff; |
| |
| /* IP header checks: fragment, too short. */ |
| if (proto != IPPROTO_TCP || otcplen < sizeof(struct tcphdr)) { |
| pr_debug("proto(%d) != IPPROTO_TCP, " |
| "or too short. otcplen = %d\n", |
| proto, otcplen); |
| return; |
| } |
| |
| if (skb_copy_bits(oldskb, tcphoff, &otcph, sizeof(struct tcphdr))) |
| BUG(); |
| |
| /* No RST for RST. */ |
| if (otcph.rst) { |
| pr_debug("RST is set\n"); |
| return; |
| } |
| |
| /* Check checksum. */ |
| if (nf_ip6_checksum(oldskb, hook, tcphoff, IPPROTO_TCP)) { |
| pr_debug("TCP checksum is invalid\n"); |
| return; |
| } |
| |
| memset(&fl6, 0, sizeof(fl6)); |
| fl6.flowi6_proto = IPPROTO_TCP; |
| fl6.saddr = oip6h->daddr; |
| fl6.daddr = oip6h->saddr; |
| fl6.fl6_sport = otcph.dest; |
| fl6.fl6_dport = otcph.source; |
| security_skb_classify_flow(oldskb, flowi6_to_flowi(&fl6)); |
| dst = ip6_route_output(net, NULL, &fl6); |
| if (dst == NULL || dst->error) { |
| dst_release(dst); |
| return; |
| } |
| dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0); |
| if (IS_ERR(dst)) |
| return; |
| |
| hh_len = (dst->dev->hard_header_len + 15)&~15; |
| nskb = alloc_skb(hh_len + 15 + dst->header_len + sizeof(struct ipv6hdr) |
| + sizeof(struct tcphdr) + dst->trailer_len, |
| GFP_ATOMIC); |
| |
| if (!nskb) { |
| net_dbg_ratelimited("cannot alloc skb\n"); |
| dst_release(dst); |
| return; |
| } |
| |
| skb_dst_set(nskb, dst); |
| |
| skb_reserve(nskb, hh_len + dst->header_len); |
| |
| skb_put(nskb, sizeof(struct ipv6hdr)); |
| skb_reset_network_header(nskb); |
| ip6h = ipv6_hdr(nskb); |
| ip6_flow_hdr(ip6h, tclass, 0); |
| ip6h->hop_limit = ip6_dst_hoplimit(dst); |
| ip6h->nexthdr = IPPROTO_TCP; |
| ip6h->saddr = oip6h->daddr; |
| ip6h->daddr = oip6h->saddr; |
| |
| skb_reset_transport_header(nskb); |
| tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr)); |
| /* Truncate to length (no data) */ |
| tcph->doff = sizeof(struct tcphdr)/4; |
| tcph->source = otcph.dest; |
| tcph->dest = otcph.source; |
| |
| if (otcph.ack) { |
| needs_ack = 0; |
| tcph->seq = otcph.ack_seq; |
| tcph->ack_seq = 0; |
| } else { |
| needs_ack = 1; |
| tcph->ack_seq = htonl(ntohl(otcph.seq) + otcph.syn + otcph.fin |
| + otcplen - (otcph.doff<<2)); |
| tcph->seq = 0; |
| } |
| |
| /* Reset flags */ |
| ((u_int8_t *)tcph)[13] = 0; |
| tcph->rst = 1; |
| tcph->ack = needs_ack; |
| tcph->window = 0; |
| tcph->urg_ptr = 0; |
| tcph->check = 0; |
| |
| /* Adjust TCP checksum */ |
| tcph->check = csum_ipv6_magic(&ipv6_hdr(nskb)->saddr, |
| &ipv6_hdr(nskb)->daddr, |
| sizeof(struct tcphdr), IPPROTO_TCP, |
| csum_partial(tcph, |
| sizeof(struct tcphdr), 0)); |
| |
| nf_ct_attach(nskb, oldskb); |
| |
| #ifdef CONFIG_BRIDGE_NETFILTER |
| /* If we use ip6_local_out for bridged traffic, the MAC source on |
| * the RST will be ours, instead of the destination's. This confuses |
| * some routers/firewalls, and they drop the packet. So we need to |
| * build the eth header using the original destination's MAC as the |
| * source, and send the RST packet directly. |
| */ |
| if (oldskb->nf_bridge) { |
| struct ethhdr *oeth = eth_hdr(oldskb); |
| nskb->dev = oldskb->nf_bridge->physindev; |
| nskb->protocol = htons(ETH_P_IPV6); |
| ip6h->payload_len = htons(sizeof(struct tcphdr)); |
| if (dev_hard_header(nskb, nskb->dev, ntohs(nskb->protocol), |
| oeth->h_source, oeth->h_dest, nskb->len) < 0) |
| return; |
| dev_queue_xmit(nskb); |
| } else |
| #endif |
| ip6_local_out(nskb); |
| } |
| |
| #endif /* _IPV6_NF_REJECT_H */ |