From: Pablo Neira Ayuso Date: Wed, 24 Mar 2021 02:30:40 +0100 Subject: [PATCH] netfilter: flowtable: use dev_fill_forward_path() to obtain egress device The egress device in the tuple is obtained from route. Use dev_fill_forward_path() instead to provide the real egress device for this flow whenever this is available. The new FLOW_OFFLOAD_XMIT_DIRECT type uses dev_queue_xmit() to transmit ethernet frames. Cache the source and destination hardware address to use dev_queue_xmit() to transfer packets. The FLOW_OFFLOAD_XMIT_DIRECT replaces FLOW_OFFLOAD_XMIT_NEIGH if dev_fill_forward_path() finds a direct transmit path. In case of topology updates, if peer is moved to different bridge port, the connection will time out, reconnect will result in a new entry with the correct path. Snooping fdb updates would allow for cleaning up stale flowtable entries. Signed-off-by: Pablo Neira Ayuso --- --- a/include/net/netfilter/nf_flow_table.h +++ b/include/net/netfilter/nf_flow_table.h @@ -92,6 +92,7 @@ enum flow_offload_tuple_dir { enum flow_offload_xmit_type { FLOW_OFFLOAD_XMIT_NEIGH = 0, FLOW_OFFLOAD_XMIT_XFRM, + FLOW_OFFLOAD_XMIT_DIRECT, }; struct flow_offload_tuple { @@ -120,8 +121,14 @@ struct flow_offload_tuple { xmit_type:2; u16 mtu; - - struct dst_entry *dst_cache; + union { + struct dst_entry *dst_cache; + struct { + u32 ifidx; + u8 h_source[ETH_ALEN]; + u8 h_dest[ETH_ALEN]; + } out; + }; }; struct flow_offload_tuple_rhash { @@ -167,6 +174,11 @@ struct nf_flow_route { struct { u32 ifindex; } in; + struct { + u32 ifindex; + u8 h_source[ETH_ALEN]; + u8 h_dest[ETH_ALEN]; + } out; enum flow_offload_xmit_type xmit_type; } tuple[FLOW_OFFLOAD_DIR_MAX]; }; --- a/net/netfilter/nf_flow_table_core.c +++ b/net/netfilter/nf_flow_table_core.c @@ -81,9 +81,6 @@ static int flow_offload_fill_route(struc struct flow_offload_tuple *flow_tuple = &flow->tuplehash[dir].tuple; struct dst_entry *dst = route->tuple[dir].dst; - if (!dst_hold_safe(route->tuple[dir].dst)) - return -1; - switch (flow_tuple->l3proto) { case NFPROTO_IPV4: flow_tuple->mtu = ip_dst_mtu_maybe_forward(dst, true); @@ -94,12 +91,36 @@ static int flow_offload_fill_route(struc } flow_tuple->iifidx = route->tuple[dir].in.ifindex; + + switch (route->tuple[dir].xmit_type) { + case FLOW_OFFLOAD_XMIT_DIRECT: + memcpy(flow_tuple->out.h_dest, route->tuple[dir].out.h_dest, + ETH_ALEN); + memcpy(flow_tuple->out.h_source, route->tuple[dir].out.h_source, + ETH_ALEN); + flow_tuple->out.ifidx = route->tuple[dir].out.ifindex; + break; + case FLOW_OFFLOAD_XMIT_XFRM: + case FLOW_OFFLOAD_XMIT_NEIGH: + if (!dst_hold_safe(route->tuple[dir].dst)) + return -1; + + flow_tuple->dst_cache = dst; + break; + } flow_tuple->xmit_type = route->tuple[dir].xmit_type; - flow_tuple->dst_cache = dst; return 0; } +static void nft_flow_dst_release(struct flow_offload *flow, + enum flow_offload_tuple_dir dir) +{ + if (flow->tuplehash[dir].tuple.xmit_type == FLOW_OFFLOAD_XMIT_NEIGH || + flow->tuplehash[dir].tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM) + dst_release(flow->tuplehash[dir].tuple.dst_cache); +} + int flow_offload_route_init(struct flow_offload *flow, const struct nf_flow_route *route) { @@ -118,7 +139,7 @@ int flow_offload_route_init(struct flow_ return 0; err_route_reply: - dst_release(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst); + nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_ORIGINAL); return err; } @@ -169,8 +190,8 @@ static void flow_offload_fixup_ct(struct static void flow_offload_route_release(struct flow_offload *flow) { - dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache); - dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache); + nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_ORIGINAL); + nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_REPLY); } void flow_offload_free(struct flow_offload *flow) --- a/net/netfilter/nf_flow_table_ip.c +++ b/net/netfilter/nf_flow_table_ip.c @@ -207,6 +207,24 @@ static unsigned int nf_flow_xmit_xfrm(st return NF_STOLEN; } +static unsigned int nf_flow_queue_xmit(struct net *net, struct sk_buff *skb, + const struct flow_offload_tuple_rhash *tuplehash, + unsigned short type) +{ + struct net_device *outdev; + + outdev = dev_get_by_index_rcu(net, tuplehash->tuple.out.ifidx); + if (!outdev) + return NF_DROP; + + skb->dev = outdev; + dev_hard_header(skb, skb->dev, type, tuplehash->tuple.out.h_dest, + tuplehash->tuple.out.h_source, skb->len); + dev_queue_xmit(skb); + + return NF_STOLEN; +} + unsigned int nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) @@ -222,6 +240,7 @@ nf_flow_offload_ip_hook(void *priv, stru struct iphdr *iph; __be32 nexthop; u32 hdrsize; + int ret; if (skb->protocol != htons(ETH_P_IP)) return NF_ACCEPT; @@ -244,9 +263,13 @@ nf_flow_offload_ip_hook(void *priv, stru if (nf_flow_state_check(flow, iph->protocol, skb, thoff)) return NF_ACCEPT; - if (!dst_check(&rt->dst, 0)) { - flow_offload_teardown(flow); - return NF_ACCEPT; + if (tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_NEIGH || + tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM) { + rt = (struct rtable *)tuplehash->tuple.dst_cache; + if (!dst_check(&rt->dst, 0)) { + flow_offload_teardown(flow); + return NF_ACCEPT; + } } if (skb_try_make_writable(skb, thoff + hdrsize)) @@ -263,8 +286,6 @@ nf_flow_offload_ip_hook(void *priv, stru if (flow_table->flags & NF_FLOWTABLE_COUNTER) nf_ct_acct_update(flow->ct, tuplehash->tuple.dir, skb->len); - rt = (struct rtable *)tuplehash->tuple.dst_cache; - if (unlikely(tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)) { memset(skb->cb, 0, sizeof(struct inet_skb_parm)); IPCB(skb)->iif = skb->dev->ifindex; @@ -272,13 +293,23 @@ nf_flow_offload_ip_hook(void *priv, stru return nf_flow_xmit_xfrm(skb, state, &rt->dst); } - outdev = rt->dst.dev; - skb->dev = outdev; - nexthop = rt_nexthop(rt, flow->tuplehash[!dir].tuple.src_v4.s_addr); - skb_dst_set_noref(skb, &rt->dst); - neigh_xmit(NEIGH_ARP_TABLE, outdev, &nexthop, skb); + switch (tuplehash->tuple.xmit_type) { + case FLOW_OFFLOAD_XMIT_NEIGH: + outdev = rt->dst.dev; + skb->dev = outdev; + nexthop = rt_nexthop(rt, flow->tuplehash[!dir].tuple.src_v4.s_addr); + skb_dst_set_noref(skb, &rt->dst); + neigh_xmit(NEIGH_ARP_TABLE, outdev, &nexthop, skb); + ret = NF_STOLEN; + break; + case FLOW_OFFLOAD_XMIT_DIRECT: + ret = nf_flow_queue_xmit(state->net, skb, tuplehash, ETH_P_IP); + if (ret == NF_DROP) + flow_offload_teardown(flow); + break; + } - return NF_STOLEN; + return ret; } EXPORT_SYMBOL_GPL(nf_flow_offload_ip_hook); @@ -444,6 +475,7 @@ nf_flow_offload_ipv6_hook(void *priv, st struct ipv6hdr *ip6h; struct rt6_info *rt; u32 hdrsize; + int ret; if (skb->protocol != htons(ETH_P_IPV6)) return NF_ACCEPT; @@ -465,9 +497,13 @@ nf_flow_offload_ipv6_hook(void *priv, st sizeof(*ip6h))) return NF_ACCEPT; - if (!dst_check(&rt->dst, 0)) { - flow_offload_teardown(flow); - return NF_ACCEPT; + if (tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_NEIGH || + tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM) { + rt = (struct rt6_info *)tuplehash->tuple.dst_cache; + if (!dst_check(&rt->dst, 0)) { + flow_offload_teardown(flow); + return NF_ACCEPT; + } } if (skb_try_make_writable(skb, sizeof(*ip6h) + hdrsize)) @@ -484,8 +520,6 @@ nf_flow_offload_ipv6_hook(void *priv, st if (flow_table->flags & NF_FLOWTABLE_COUNTER) nf_ct_acct_update(flow->ct, tuplehash->tuple.dir, skb->len); - rt = (struct rt6_info *)tuplehash->tuple.dst_cache; - if (unlikely(tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)) { memset(skb->cb, 0, sizeof(struct inet6_skb_parm)); IP6CB(skb)->iif = skb->dev->ifindex; @@ -493,12 +527,22 @@ nf_flow_offload_ipv6_hook(void *priv, st return nf_flow_xmit_xfrm(skb, state, &rt->dst); } - outdev = rt->dst.dev; - skb->dev = outdev; - nexthop = rt6_nexthop(rt, &flow->tuplehash[!dir].tuple.src_v6); - skb_dst_set_noref(skb, &rt->dst); - neigh_xmit(NEIGH_ND_TABLE, outdev, nexthop, skb); + switch (tuplehash->tuple.xmit_type) { + case FLOW_OFFLOAD_XMIT_NEIGH: + outdev = rt->dst.dev; + skb->dev = outdev; + nexthop = rt6_nexthop(rt, &flow->tuplehash[!dir].tuple.src_v6); + skb_dst_set_noref(skb, &rt->dst); + neigh_xmit(NEIGH_ND_TABLE, outdev, nexthop, skb); + ret = NF_STOLEN; + break; + case FLOW_OFFLOAD_XMIT_DIRECT: + ret = nf_flow_queue_xmit(state->net, skb, tuplehash, ETH_P_IPV6); + if (ret == NF_DROP) + flow_offload_teardown(flow); + break; + } - return NF_STOLEN; + return ret; } EXPORT_SYMBOL_GPL(nf_flow_offload_ipv6_hook); --- a/net/netfilter/nft_flow_offload.c +++ b/net/netfilter/nft_flow_offload.c @@ -39,12 +39,11 @@ static void nft_default_forward_path(str static int nft_dev_fill_forward_path(const struct nf_flow_route *route, const struct dst_entry *dst_cache, const struct nf_conn *ct, - enum ip_conntrack_dir dir, + enum ip_conntrack_dir dir, u8 *ha, struct net_device_path_stack *stack) { const void *daddr = &ct->tuplehash[!dir].tuple.src.u3; struct net_device *dev = dst_cache->dev; - unsigned char ha[ETH_ALEN]; struct neighbour *n; u8 nud_state; @@ -66,27 +65,43 @@ static int nft_dev_fill_forward_path(con struct nft_forward_info { const struct net_device *indev; + const struct net_device *outdev; + u8 h_source[ETH_ALEN]; + u8 h_dest[ETH_ALEN]; + enum flow_offload_xmit_type xmit_type; }; static void nft_dev_path_info(const struct net_device_path_stack *stack, - struct nft_forward_info *info) + struct nft_forward_info *info, + unsigned char *ha) { const struct net_device_path *path; int i; + memcpy(info->h_dest, ha, ETH_ALEN); + for (i = 0; i < stack->num_paths; i++) { path = &stack->path[i]; switch (path->type) { case DEV_PATH_ETHERNET: info->indev = path->dev; + if (is_zero_ether_addr(info->h_source)) + memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN); break; - case DEV_PATH_VLAN: case DEV_PATH_BRIDGE: + if (is_zero_ether_addr(info->h_source)) + memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN); + + info->xmit_type = FLOW_OFFLOAD_XMIT_DIRECT; + break; + case DEV_PATH_VLAN: default: info->indev = NULL; break; } } + if (!info->outdev) + info->outdev = info->indev; } static bool nft_flowtable_find_dev(const struct net_device *dev, @@ -114,14 +129,22 @@ static void nft_dev_forward_path(struct const struct dst_entry *dst = route->tuple[dir].dst; struct net_device_path_stack stack; struct nft_forward_info info = {}; + unsigned char ha[ETH_ALEN]; - if (nft_dev_fill_forward_path(route, dst, ct, dir, &stack) >= 0) - nft_dev_path_info(&stack, &info); + if (nft_dev_fill_forward_path(route, dst, ct, dir, ha, &stack) >= 0) + nft_dev_path_info(&stack, &info, ha); if (!info.indev || !nft_flowtable_find_dev(info.indev, ft)) return; route->tuple[!dir].in.ifindex = info.indev->ifindex; + + if (info.xmit_type == FLOW_OFFLOAD_XMIT_DIRECT) { + memcpy(route->tuple[dir].out.h_source, info.h_source, ETH_ALEN); + memcpy(route->tuple[dir].out.h_dest, info.h_dest, ETH_ALEN); + route->tuple[dir].out.ifindex = info.outdev->ifindex; + route->tuple[dir].xmit_type = info.xmit_type; + } } static int nft_flow_route(const struct nft_pktinfo *pkt,