diff options
Diffstat (limited to 'net/ipv4/ip_gre.c')
| -rw-r--r-- | net/ipv4/ip_gre.c | 215 |
1 files changed, 199 insertions, 16 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 49d140200d03..fb44d693796e 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -123,8 +123,127 @@ static int ipgre_tunnel_init(struct net_device *dev); static int ipgre_net_id __read_mostly; static int gre_tap_net_id __read_mostly; -static int ipgre_err(struct sk_buff *skb, u32 info, - const struct tnl_ptk_info *tpi) +static int ip_gre_calc_hlen(__be16 o_flags) +{ + int addend = 4; + + if (o_flags & TUNNEL_CSUM) + addend += 4; + if (o_flags & TUNNEL_KEY) + addend += 4; + if (o_flags & TUNNEL_SEQ) + addend += 4; + return addend; +} + +static __be16 gre_flags_to_tnl_flags(__be16 flags) +{ + __be16 tflags = 0; + + if (flags & GRE_CSUM) + tflags |= TUNNEL_CSUM; + if (flags & GRE_ROUTING) + tflags |= TUNNEL_ROUTING; + if (flags & GRE_KEY) + tflags |= TUNNEL_KEY; + if (flags & GRE_SEQ) + tflags |= TUNNEL_SEQ; + if (flags & GRE_STRICT) + tflags |= TUNNEL_STRICT; + if (flags & GRE_REC) + tflags |= TUNNEL_REC; + if (flags & GRE_VERSION) + tflags |= TUNNEL_VERSION; + + return tflags; +} + +static __be16 tnl_flags_to_gre_flags(__be16 tflags) +{ + __be16 flags = 0; + + if (tflags & TUNNEL_CSUM) + flags |= GRE_CSUM; + if (tflags & TUNNEL_ROUTING) + flags |= GRE_ROUTING; + if (tflags & TUNNEL_KEY) + flags |= GRE_KEY; + if (tflags & TUNNEL_SEQ) + flags |= GRE_SEQ; + if (tflags & TUNNEL_STRICT) + flags |= GRE_STRICT; + if (tflags & TUNNEL_REC) + flags |= GRE_REC; + if (tflags & TUNNEL_VERSION) + flags |= GRE_VERSION; + + return flags; +} + +static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi, + bool *csum_err) +{ + const struct gre_base_hdr *greh; + __be32 *options; + int hdr_len; + + if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr)))) + return -EINVAL; + + greh = (struct gre_base_hdr *)skb_transport_header(skb); + if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING))) + return -EINVAL; + + tpi->flags = gre_flags_to_tnl_flags(greh->flags); + hdr_len = ip_gre_calc_hlen(tpi->flags); + + if (!pskb_may_pull(skb, hdr_len)) + return -EINVAL; + + greh = (struct gre_base_hdr *)skb_transport_header(skb); + tpi->proto = greh->protocol; + + options = (__be32 *)(greh + 1); + if (greh->flags & GRE_CSUM) { + if (skb_checksum_simple_validate(skb)) { + *csum_err = true; + return -EINVAL; + } + + skb_checksum_try_convert(skb, IPPROTO_GRE, 0, + null_compute_pseudo); + options++; + } + + if (greh->flags & GRE_KEY) { + tpi->key = *options; + options++; + } else { + tpi->key = 0; + } + if (unlikely(greh->flags & GRE_SEQ)) { + tpi->seq = *options; + options++; + } else { + tpi->seq = 0; + } + /* WCCP version 1 and 2 protocol decoding. + * - Change protocol to IP + * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header + */ + if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) { + tpi->proto = htons(ETH_P_IP); + if ((*(u8 *)options & 0xF0) != 0x40) { + hdr_len += 4; + if (!pskb_may_pull(skb, hdr_len)) + return -EINVAL; + } + } + return iptunnel_pull_header(skb, hdr_len, tpi->proto); +} + +static void ipgre_err(struct sk_buff *skb, u32 info, + const struct tnl_ptk_info *tpi) { /* All the routers (except for Linux) return only @@ -150,14 +269,14 @@ static int ipgre_err(struct sk_buff *skb, u32 info, switch (type) { default: case ICMP_PARAMETERPROB: - return PACKET_RCVD; + return; case ICMP_DEST_UNREACH: switch (code) { case ICMP_SR_FAILED: case ICMP_PORT_UNREACH: /* Impossible event. */ - return PACKET_RCVD; + return; default: /* All others are translated to HOST_UNREACH. rfc2003 contains "deep thoughts" about NET_UNREACH, @@ -166,9 +285,10 @@ static int ipgre_err(struct sk_buff *skb, u32 info, break; } break; + case ICMP_TIME_EXCEEDED: if (code != ICMP_EXC_TTL) - return PACKET_RCVD; + return; break; case ICMP_REDIRECT: @@ -185,21 +305,60 @@ static int ipgre_err(struct sk_buff *skb, u32 info, iph->daddr, iph->saddr, tpi->key); if (!t) - return PACKET_REJECT; + return; if (t->parms.iph.daddr == 0 || ipv4_is_multicast(t->parms.iph.daddr)) - return PACKET_RCVD; + return; if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED) - return PACKET_RCVD; + return; if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO)) t->err_count++; else t->err_count = 1; t->err_time = jiffies; - return PACKET_RCVD; +} + +static void gre_err(struct sk_buff *skb, u32 info) +{ + /* All the routers (except for Linux) return only + * 8 bytes of packet payload. It means, that precise relaying of + * ICMP in the real Internet is absolutely infeasible. + * + * Moreover, Cisco "wise men" put GRE key to the third word + * in GRE header. It makes impossible maintaining even soft + * state for keyed + * GRE tunnels with enabled checksum. Tell them "thank you". + * + * Well, I wonder, rfc1812 was written by Cisco employee, + * what the hell these idiots break standards established + * by themselves??? + */ + + const int type = icmp_hdr(skb)->type; + const int code = icmp_hdr(skb)->code; + struct tnl_ptk_info tpi; + bool csum_err = false; + + if (parse_gre_header(skb, &tpi, &csum_err)) { + if (!csum_err) /* ignore csum errors. */ + return; + } + + if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) { + ipv4_update_pmtu(skb, dev_net(skb->dev), info, + skb->dev->ifindex, 0, IPPROTO_GRE, 0); + return; + } + if (type == ICMP_REDIRECT) { + ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 0, + IPPROTO_GRE, 0); + return; + } + + ipgre_err(skb, info, &tpi); } static __be64 key_to_tunnel_id(__be32 key) @@ -268,6 +427,31 @@ static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi) return PACKET_REJECT; } +static int gre_rcv(struct sk_buff *skb) +{ + struct tnl_ptk_info tpi; + bool csum_err = false; + +#ifdef CONFIG_NET_IPGRE_BROADCAST + if (ipv4_is_multicast(ip_hdr(skb)->daddr)) { + /* Looped back packet, drop it! */ + if (rt_is_output_route(skb_rtable(skb))) + goto drop; + } +#endif + + if (parse_gre_header(skb, &tpi, &csum_err) < 0) + goto drop; + + if (ipgre_rcv(skb, &tpi) == PACKET_RCVD) + return 0; + + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); +drop: + kfree_skb(skb); + return 0; +} + static void build_header(struct sk_buff *skb, int hdr_len, __be16 flags, __be16 proto, __be32 key, __be32 seq) { @@ -684,10 +868,9 @@ static int ipgre_tunnel_init(struct net_device *dev) return ip_tunnel_init(dev); } -static struct gre_cisco_protocol ipgre_protocol = { - .handler = ipgre_rcv, - .err_handler = ipgre_err, - .priority = 0, +static const struct gre_protocol ipgre_protocol = { + .handler = gre_rcv, + .err_handler = gre_err, }; static int __net_init ipgre_init_net(struct net *net) @@ -1080,7 +1263,7 @@ static int __init ipgre_init(void) if (err < 0) goto pnet_tap_faied; - err = gre_cisco_register(&ipgre_protocol); + err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO); if (err < 0) { pr_info("%s: can't add protocol\n", __func__); goto add_proto_failed; @@ -1099,7 +1282,7 @@ static int __init ipgre_init(void) tap_ops_failed: rtnl_link_unregister(&ipgre_link_ops); rtnl_link_failed: - gre_cisco_unregister(&ipgre_protocol); + gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO); add_proto_failed: unregister_pernet_device(&ipgre_tap_net_ops); pnet_tap_faied: @@ -1111,7 +1294,7 @@ static void __exit ipgre_fini(void) { rtnl_link_unregister(&ipgre_tap_ops); rtnl_link_unregister(&ipgre_link_ops); - gre_cisco_unregister(&ipgre_protocol); + gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO); unregister_pernet_device(&ipgre_tap_net_ops); unregister_pernet_device(&ipgre_net_ops); } |