diff options
author | Eric Leblond <eric@regit.org> | 2013-12-29 12:28:13 +0100 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2013-12-30 15:04:41 +0100 |
commit | cc70d069e2b9cece683206c0f6a1d1484414e577 (patch) | |
tree | be91bf60de5839a92b5f9edf9adb156b91e473a0 /net | |
parent | 5f291c2869a08a63dbdc9de3e13ac5f2d5ed8d47 (diff) | |
download | linux-cc70d069e2b9cece683206c0f6a1d1484414e577.tar.bz2 |
netfilter: REJECT: separate reusable code
This patch prepares the addition of TCP reset support in
the nft_reject module by moving reusable code into a header
file.
Signed-off-by: Eric Leblond <eric@regit.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r-- | net/ipv4/netfilter/ipt_REJECT.c | 140 | ||||
-rw-r--r-- | net/ipv6/netfilter/ip6t_REJECT.c | 179 |
2 files changed, 18 insertions, 301 deletions
diff --git a/net/ipv4/netfilter/ipt_REJECT.c b/net/ipv4/netfilter/ipt_REJECT.c index b969131ad1c1..5b6e0df4ccff 100644 --- a/net/ipv4/netfilter/ipt_REJECT.c +++ b/net/ipv4/netfilter/ipt_REJECT.c @@ -17,10 +17,6 @@ #include <linux/udp.h> #include <linux/icmp.h> #include <net/icmp.h> -#include <net/ip.h> -#include <net/tcp.h> -#include <net/route.h> -#include <net/dst.h> #include <linux/netfilter/x_tables.h> #include <linux/netfilter_ipv4/ip_tables.h> #include <linux/netfilter_ipv4/ipt_REJECT.h> @@ -28,128 +24,12 @@ #include <linux/netfilter_bridge.h> #endif +#include <net/netfilter/ipv4/nf_reject.h> + MODULE_LICENSE("GPL"); MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv4"); -/* Send RST reply */ -static void send_reset(struct sk_buff *oldskb, int hook) -{ - struct sk_buff *nskb; - const struct iphdr *oiph; - struct iphdr *niph; - const struct tcphdr *oth; - struct tcphdr _otcph, *tcph; - - /* IP header checks: fragment. */ - if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET)) - return; - - oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb), - sizeof(_otcph), &_otcph); - if (oth == NULL) - return; - - /* No RST for RST. */ - if (oth->rst) - return; - - if (skb_rtable(oldskb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) - return; - - /* Check checksum */ - if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP)) - return; - oiph = ip_hdr(oldskb); - - nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) + - LL_MAX_HEADER, GFP_ATOMIC); - if (!nskb) - return; - - skb_reserve(nskb, LL_MAX_HEADER); - - skb_reset_network_header(nskb); - niph = (struct iphdr *)skb_put(nskb, sizeof(struct iphdr)); - niph->version = 4; - niph->ihl = sizeof(struct iphdr) / 4; - niph->tos = 0; - niph->id = 0; - niph->frag_off = htons(IP_DF); - niph->protocol = IPPROTO_TCP; - niph->check = 0; - niph->saddr = oiph->daddr; - niph->daddr = oiph->saddr; - - skb_reset_transport_header(nskb); - tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr)); - memset(tcph, 0, sizeof(*tcph)); - tcph->source = oth->dest; - tcph->dest = oth->source; - tcph->doff = sizeof(struct tcphdr) / 4; - - if (oth->ack) - tcph->seq = oth->ack_seq; - else { - tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin + - oldskb->len - ip_hdrlen(oldskb) - - (oth->doff << 2)); - tcph->ack = 1; - } - - tcph->rst = 1; - tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), niph->saddr, - niph->daddr, 0); - nskb->ip_summed = CHECKSUM_PARTIAL; - nskb->csum_start = (unsigned char *)tcph - nskb->head; - nskb->csum_offset = offsetof(struct tcphdr, check); - - /* ip_route_me_harder expects skb->dst to be set */ - skb_dst_set_noref(nskb, skb_dst(oldskb)); - - nskb->protocol = htons(ETH_P_IP); - if (ip_route_me_harder(nskb, RTN_UNSPEC)) - goto free_nskb; - - niph->ttl = ip4_dst_hoplimit(skb_dst(nskb)); - - /* "Never happens" */ - if (nskb->len > dst_mtu(skb_dst(nskb))) - goto free_nskb; - - nf_ct_attach(nskb, oldskb); - -#ifdef CONFIG_BRIDGE_NETFILTER - /* If we use ip_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; - niph->tot_len = htons(nskb->len); - ip_send_check(niph); - if (dev_hard_header(nskb, nskb->dev, ntohs(nskb->protocol), - oeth->h_source, oeth->h_dest, nskb->len) < 0) - goto free_nskb; - dev_queue_xmit(nskb); - } else -#endif - ip_local_out(nskb); - - return; - - free_nskb: - kfree_skb(nskb); -} - -static inline void send_unreach(struct sk_buff *skb_in, int code) -{ - icmp_send(skb_in, ICMP_DEST_UNREACH, code, 0); -} - static unsigned int reject_tg(struct sk_buff *skb, const struct xt_action_param *par) { @@ -157,28 +37,28 @@ reject_tg(struct sk_buff *skb, const struct xt_action_param *par) switch (reject->with) { case IPT_ICMP_NET_UNREACHABLE: - send_unreach(skb, ICMP_NET_UNREACH); + nf_send_unreach(skb, ICMP_NET_UNREACH); break; case IPT_ICMP_HOST_UNREACHABLE: - send_unreach(skb, ICMP_HOST_UNREACH); + nf_send_unreach(skb, ICMP_HOST_UNREACH); break; case IPT_ICMP_PROT_UNREACHABLE: - send_unreach(skb, ICMP_PROT_UNREACH); + nf_send_unreach(skb, ICMP_PROT_UNREACH); break; case IPT_ICMP_PORT_UNREACHABLE: - send_unreach(skb, ICMP_PORT_UNREACH); + nf_send_unreach(skb, ICMP_PORT_UNREACH); break; case IPT_ICMP_NET_PROHIBITED: - send_unreach(skb, ICMP_NET_ANO); + nf_send_unreach(skb, ICMP_NET_ANO); break; case IPT_ICMP_HOST_PROHIBITED: - send_unreach(skb, ICMP_HOST_ANO); + nf_send_unreach(skb, ICMP_HOST_ANO); break; case IPT_ICMP_ADMIN_PROHIBITED: - send_unreach(skb, ICMP_PKT_FILTERED); + nf_send_unreach(skb, ICMP_PKT_FILTERED); break; case IPT_TCP_RESET: - send_reset(skb, par->hooknum); + nf_send_reset(skb, par->hooknum); case IPT_ICMP_ECHOREPLY: /* Doesn't happen. */ break; diff --git a/net/ipv6/netfilter/ip6t_REJECT.c b/net/ipv6/netfilter/ip6t_REJECT.c index da00a2ecde55..544b0a9da1b5 100644 --- a/net/ipv6/netfilter/ip6t_REJECT.c +++ b/net/ipv6/netfilter/ip6t_REJECT.c @@ -23,181 +23,18 @@ #include <linux/skbuff.h> #include <linux/icmpv6.h> #include <linux/netdevice.h> -#include <net/ipv6.h> -#include <net/tcp.h> #include <net/icmp.h> -#include <net/ip6_checksum.h> -#include <net/ip6_fib.h> -#include <net/ip6_route.h> #include <net/flow.h> #include <linux/netfilter/x_tables.h> #include <linux/netfilter_ipv6/ip6_tables.h> #include <linux/netfilter_ipv6/ip6t_REJECT.h> +#include <net/netfilter/ipv6/nf_reject.h> + MODULE_AUTHOR("Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>"); MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv6"); MODULE_LICENSE("GPL"); -/* Send RST reply */ -static void send_reset(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); -} - -static inline void -send_unreach(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); -} static unsigned int reject_tg6(struct sk_buff *skb, const struct xt_action_param *par) @@ -208,25 +45,25 @@ reject_tg6(struct sk_buff *skb, const struct xt_action_param *par) pr_debug("%s: medium point\n", __func__); switch (reject->with) { case IP6T_ICMP6_NO_ROUTE: - send_unreach(net, skb, ICMPV6_NOROUTE, par->hooknum); + nf_send_unreach6(net, skb, ICMPV6_NOROUTE, par->hooknum); break; case IP6T_ICMP6_ADM_PROHIBITED: - send_unreach(net, skb, ICMPV6_ADM_PROHIBITED, par->hooknum); + nf_send_unreach6(net, skb, ICMPV6_ADM_PROHIBITED, par->hooknum); break; case IP6T_ICMP6_NOT_NEIGHBOUR: - send_unreach(net, skb, ICMPV6_NOT_NEIGHBOUR, par->hooknum); + nf_send_unreach6(net, skb, ICMPV6_NOT_NEIGHBOUR, par->hooknum); break; case IP6T_ICMP6_ADDR_UNREACH: - send_unreach(net, skb, ICMPV6_ADDR_UNREACH, par->hooknum); + nf_send_unreach6(net, skb, ICMPV6_ADDR_UNREACH, par->hooknum); break; case IP6T_ICMP6_PORT_UNREACH: - send_unreach(net, skb, ICMPV6_PORT_UNREACH, par->hooknum); + nf_send_unreach6(net, skb, ICMPV6_PORT_UNREACH, par->hooknum); break; case IP6T_ICMP6_ECHOREPLY: /* Do nothing */ break; case IP6T_TCP_RESET: - send_reset(net, skb, par->hooknum); + nf_send_reset6(net, skb, par->hooknum); break; default: net_info_ratelimited("case %u not handled yet\n", reject->with); |