target/linux/generic/pending-5.10/640-06-netfilter-flowtable-use-dev_fill_forward_path-to-obt.patch

   1 From: Pablo Neira Ayuso <pablo@netfilter.org>
   2 Date: Fri, 20 Nov 2020 13:49:19 +0100
   3 Subject: [PATCH] netfilter: flowtable: use dev_fill_forward_path() to
   4  obtain egress device
   5
   6 The egress device in the tuple is obtained from route. Use
   7 dev_fill_forward_path() instead to provide the real egress device for
   8 this flow whenever this is available.
   9
  10 The new FLOW_OFFLOAD_XMIT_DIRECT type uses dev_queue_xmit() to transmit
  11 ethernet frames. Cache the source and destination hardware address to
  12 use dev_queue_xmit() to transfer packets.
  13
  14 The FLOW_OFFLOAD_XMIT_DIRECT replaces FLOW_OFFLOAD_XMIT_NEIGH if
  15 dev_fill_forward_path() finds a direct transmit path.
  16
  17 In case of topology updates, if peer is moved to different bridge port,
  18 the connection will time out, reconnect will result in a new entry with
  19 the correct path. Snooping fdb updates would allow for cleaning up stale
  20 flowtable entries.
  21
  22 Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
  23 ---
  24
  25 --- a/include/net/netfilter/nf_flow_table.h
  26 +++ b/include/net/netfilter/nf_flow_table.h
  27 @@ -92,6 +92,7 @@ enum flow_offload_tuple_dir {
  28  enum flow_offload_xmit_type {
  29         FLOW_OFFLOAD_XMIT_NEIGH         = 0,
  30         FLOW_OFFLOAD_XMIT_XFRM,
  31 +       FLOW_OFFLOAD_XMIT_DIRECT,
  32  };
  33
  34  struct flow_offload_tuple {
  35 @@ -120,8 +121,14 @@ struct flow_offload_tuple {
  36                                         xmit_type:2;
  37
  38         u16                             mtu;
  39 -
  40 -       struct dst_entry                *dst_cache;
  41 +       union {
  42 +               struct dst_entry        *dst_cache;
  43 +               struct {
  44 +                       u32             ifidx;
  45 +                       u8              h_source[ETH_ALEN];
  46 +                       u8              h_dest[ETH_ALEN];
  47 +               } out;
  48 +       };
  49  };
  50
  51  struct flow_offload_tuple_rhash {
  52 @@ -168,6 +175,11 @@ struct nf_flow_route {
  53                 struct {
  54                         u32                     ifindex;
  55                 } in;
  56 +               struct {
  57 +                       u32                     ifindex;
  58 +                       u8                      h_source[ETH_ALEN];
  59 +                       u8                      h_dest[ETH_ALEN];
  60 +               } out;
  61                 enum flow_offload_xmit_type     xmit_type;
  62         } tuple[FLOW_OFFLOAD_DIR_MAX];
  63  };
  64 --- a/net/netfilter/nf_flow_table_core.c
  65 +++ b/net/netfilter/nf_flow_table_core.c
  66 @@ -81,9 +81,6 @@ static int flow_offload_fill_route(struc
  67         struct flow_offload_tuple *flow_tuple = &flow->tuplehash[dir].tuple;
  68         struct dst_entry *dst = route->tuple[dir].dst;
  69
  70 -       if (!dst_hold_safe(route->tuple[dir].dst))
  71 -               return -1;
  72 -
  73         switch (flow_tuple->l3proto) {
  74         case NFPROTO_IPV4:
  75                 flow_tuple->mtu = ip_dst_mtu_maybe_forward(dst, true);
  76 @@ -94,12 +91,36 @@ static int flow_offload_fill_route(struc
  77         }
  78
  79         flow_tuple->iifidx = route->tuple[dir].in.ifindex;
  80 +
  81 +       switch (route->tuple[dir].xmit_type) {
  82 +       case FLOW_OFFLOAD_XMIT_DIRECT:
  83 +               memcpy(flow_tuple->out.h_dest, route->tuple[dir].out.h_dest,
  84 +                      ETH_ALEN);
  85 +               memcpy(flow_tuple->out.h_source, route->tuple[dir].out.h_source,
  86 +                      ETH_ALEN);
  87 +               flow_tuple->out.ifidx = route->tuple[dir].out.ifindex;
  88 +               break;
  89 +       case FLOW_OFFLOAD_XMIT_XFRM:
  90 +       case FLOW_OFFLOAD_XMIT_NEIGH:
  91 +               if (!dst_hold_safe(route->tuple[dir].dst))
  92 +                       return -1;
  93 +
  94 +               flow_tuple->dst_cache = dst;
  95 +               break;
  96 +       }
  97         flow_tuple->xmit_type = route->tuple[dir].xmit_type;
  98 -       flow_tuple->dst_cache = dst;
  99
 100         return 0;
 101  }
 102
 103 +static void nft_flow_dst_release(struct flow_offload *flow,
 104 +                                enum flow_offload_tuple_dir dir)
 105 +{
 106 +       if (flow->tuplehash[dir].tuple.xmit_type == FLOW_OFFLOAD_XMIT_NEIGH ||
 107 +           flow->tuplehash[dir].tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)
 108 +               dst_release(flow->tuplehash[dir].tuple.dst_cache);
 109 +}
 110 +
 111  int flow_offload_route_init(struct flow_offload *flow,
 112                             const struct nf_flow_route *route)
 113  {
 114 @@ -118,7 +139,7 @@ int flow_offload_route_init(struct flow_
 115         return 0;
 116
 117  err_route_reply:
 118 -       dst_release(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst);
 119 +       nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_ORIGINAL);
 120
 121         return err;
 122  }
 123 @@ -169,8 +190,8 @@ static void flow_offload_fixup_ct(struct
 124
 125  static void flow_offload_route_release(struct flow_offload *flow)
 126  {
 127 -       dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache);
 128 -       dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache);
 129 +       nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_ORIGINAL);
 130 +       nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_REPLY);
 131  }
 132
 133  void flow_offload_free(struct flow_offload *flow)
 134 --- a/net/netfilter/nf_flow_table_ip.c
 135 +++ b/net/netfilter/nf_flow_table_ip.c
 136 @@ -248,6 +248,24 @@ static unsigned int nf_flow_xmit_xfrm(st
 137         return NF_STOLEN;
 138  }
 139
 140 +static unsigned int nf_flow_queue_xmit(struct net *net, struct sk_buff *skb,
 141 +                                      const struct flow_offload_tuple_rhash *tuplehash,
 142 +                                      unsigned short type)
 143 +{
 144 +       struct net_device *outdev;
 145 +
 146 +       outdev = dev_get_by_index_rcu(net, tuplehash->tuple.out.ifidx);
 147 +       if (!outdev)
 148 +               return NF_DROP;
 149 +
 150 +       skb->dev = outdev;
 151 +       dev_hard_header(skb, skb->dev, type, tuplehash->tuple.out.h_dest,
 152 +                       tuplehash->tuple.out.h_source, skb->len);
 153 +       dev_queue_xmit(skb);
 154 +
 155 +       return NF_STOLEN;
 156 +}
 157 +
 158  unsigned int
 159  nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
 160                         const struct nf_hook_state *state)
 161 @@ -262,6 +280,7 @@ nf_flow_offload_ip_hook(void *priv, stru
 162         unsigned int thoff;
 163         struct iphdr *iph;
 164         __be32 nexthop;
 165 +       int ret;
 166
 167         if (skb->protocol != htons(ETH_P_IP))
 168                 return NF_ACCEPT;
 169 @@ -303,22 +322,32 @@ nf_flow_offload_ip_hook(void *priv, stru
 170         if (flow_table->flags & NF_FLOWTABLE_COUNTER)
 171                 nf_ct_acct_update(flow->ct, tuplehash->tuple.dir, skb->len);
 172
 173 -       rt = (struct rtable *)tuplehash->tuple.dst_cache;
 174 -
 175         if (unlikely(tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)) {
 176 +               rt = (struct rtable *)tuplehash->tuple.dst_cache;
 177                 memset(skb->cb, 0, sizeof(struct inet_skb_parm));
 178                 IPCB(skb)->iif = skb->dev->ifindex;
 179                 IPCB(skb)->flags = IPSKB_FORWARDED;
 180                 return nf_flow_xmit_xfrm(skb, state, &rt->dst);
 181         }
 182
 183 -       outdev = rt->dst.dev;
 184 -       skb->dev = outdev;
 185 -       nexthop = rt_nexthop(rt, flow->tuplehash[!dir].tuple.src_v4.s_addr);
 186 -       skb_dst_set_noref(skb, &rt->dst);
 187 -       neigh_xmit(NEIGH_ARP_TABLE, outdev, &nexthop, skb);
 188 +       switch (tuplehash->tuple.xmit_type) {
 189 +       case FLOW_OFFLOAD_XMIT_NEIGH:
 190 +               rt = (struct rtable *)tuplehash->tuple.dst_cache;
 191 +               outdev = rt->dst.dev;
 192 +               skb->dev = outdev;
 193 +               nexthop = rt_nexthop(rt, flow->tuplehash[!dir].tuple.src_v4.s_addr);
 194 +               skb_dst_set_noref(skb, &rt->dst);
 195 +               neigh_xmit(NEIGH_ARP_TABLE, outdev, &nexthop, skb);
 196 +               ret = NF_STOLEN;
 197 +               break;
 198 +       case FLOW_OFFLOAD_XMIT_DIRECT:
 199 +               ret = nf_flow_queue_xmit(state->net, skb, tuplehash, ETH_P_IP);
 200 +               if (ret == NF_DROP)
 201 +                       flow_offload_teardown(flow);
 202 +               break;
 203 +       }
 204
 205 -       return NF_STOLEN;
 206 +       return ret;
 207  }
 208  EXPORT_SYMBOL_GPL(nf_flow_offload_ip_hook);
 209
 210 @@ -504,6 +533,7 @@ nf_flow_offload_ipv6_hook(void *priv, st
 211         struct net_device *outdev;
 212         struct ipv6hdr *ip6h;
 213         struct rt6_info *rt;
 214 +       int ret;
 215
 216         if (skb->protocol != htons(ETH_P_IPV6))
 217                 return NF_ACCEPT;
 218 @@ -545,21 +575,31 @@ nf_flow_offload_ipv6_hook(void *priv, st
 219         if (flow_table->flags & NF_FLOWTABLE_COUNTER)
 220                 nf_ct_acct_update(flow->ct, tuplehash->tuple.dir, skb->len);
 221
 222 -       rt = (struct rt6_info *)tuplehash->tuple.dst_cache;
 223 -
 224         if (unlikely(tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)) {
 225 +               rt = (struct rt6_info *)tuplehash->tuple.dst_cache;
 226                 memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
 227                 IP6CB(skb)->iif = skb->dev->ifindex;
 228                 IP6CB(skb)->flags = IP6SKB_FORWARDED;
 229                 return nf_flow_xmit_xfrm(skb, state, &rt->dst);
 230         }
 231
 232 -       outdev = rt->dst.dev;
 233 -       skb->dev = outdev;
 234 -       nexthop = rt6_nexthop(rt, &flow->tuplehash[!dir].tuple.src_v6);
 235 -       skb_dst_set_noref(skb, &rt->dst);
 236 -       neigh_xmit(NEIGH_ND_TABLE, outdev, nexthop, skb);
 237 +       switch (tuplehash->tuple.xmit_type) {
 238 +       case FLOW_OFFLOAD_XMIT_NEIGH:
 239 +               rt = (struct rt6_info *)tuplehash->tuple.dst_cache;
 240 +               outdev = rt->dst.dev;
 241 +               skb->dev = outdev;
 242 +               nexthop = rt6_nexthop(rt, &flow->tuplehash[!dir].tuple.src_v6);
 243 +               skb_dst_set_noref(skb, &rt->dst);
 244 +               neigh_xmit(NEIGH_ND_TABLE, outdev, nexthop, skb);
 245 +               ret = NF_STOLEN;
 246 +               break;
 247 +       case FLOW_OFFLOAD_XMIT_DIRECT:
 248 +               ret = nf_flow_queue_xmit(state->net, skb, tuplehash, ETH_P_IPV6);
 249 +               if (ret == NF_DROP)
 250 +                       flow_offload_teardown(flow);
 251 +               break;
 252 +       }
 253
 254 -       return NF_STOLEN;
 255 +       return ret;
 256  }
 257  EXPORT_SYMBOL_GPL(nf_flow_offload_ipv6_hook);
 258 --- a/net/netfilter/nft_flow_offload.c
 259 +++ b/net/netfilter/nft_flow_offload.c
 260 @@ -39,12 +39,11 @@ static void nft_default_forward_path(str
 261  static int nft_dev_fill_forward_path(const struct nf_flow_route *route,
 262                                      const struct dst_entry *dst_cache,
 263                                      const struct nf_conn *ct,
 264 -                                    enum ip_conntrack_dir dir,
 265 +                                    enum ip_conntrack_dir dir, u8 *ha,
 266                                      struct net_device_path_stack *stack)
 267  {
 268         const void *daddr = &ct->tuplehash[!dir].tuple.src.u3;
 269         struct net_device *dev = dst_cache->dev;
 270 -       unsigned char ha[ETH_ALEN];
 271         struct neighbour *n;
 272         u8 nud_state;
 273
 274 @@ -66,22 +65,35 @@ static int nft_dev_fill_forward_path(con
 275
 276  struct nft_forward_info {
 277         const struct net_device *dev;
 278 +       u8 h_source[ETH_ALEN];
 279 +       u8 h_dest[ETH_ALEN];
 280 +       enum flow_offload_xmit_type xmit_type;
 281  };
 282
 283  static void nft_dev_path_info(const struct net_device_path_stack *stack,
 284 -                             struct nft_forward_info *info)
 285 +                             struct nft_forward_info *info,
 286 +                             unsigned char *ha)
 287  {
 288         const struct net_device_path *path;
 289         int i;
 290
 291 +       memcpy(info->h_dest, ha, ETH_ALEN);
 292 +
 293         for (i = 0; i < stack->num_paths; i++) {
 294                 path = &stack->path[i];
 295                 switch (path->type) {
 296                 case DEV_PATH_ETHERNET:
 297                         info->dev = path->dev;
 298 +                       if (is_zero_ether_addr(info->h_source))
 299 +                               memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN);
 300                         break;
 301 -               case DEV_PATH_VLAN:
 302                 case DEV_PATH_BRIDGE:
 303 +                       if (is_zero_ether_addr(info->h_source))
 304 +                               memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN);
 305 +
 306 +                       info->xmit_type = FLOW_OFFLOAD_XMIT_DIRECT;
 307 +                       break;
 308 +               case DEV_PATH_VLAN:
 309                 default:
 310                         info->dev = NULL;
 311                         break;
 312 @@ -114,14 +126,22 @@ static void nft_dev_forward_path(struct
 313         const struct dst_entry *dst = route->tuple[dir].dst;
 314         struct net_device_path_stack stack;
 315         struct nft_forward_info info = {};
 316 +       unsigned char ha[ETH_ALEN];
 317
 318 -       if (nft_dev_fill_forward_path(route, dst, ct, dir, &stack) >= 0)
 319 -               nft_dev_path_info(&stack, &info);
 320 +       if (nft_dev_fill_forward_path(route, dst, ct, dir, ha, &stack) >= 0)
 321 +               nft_dev_path_info(&stack, &info, ha);
 322
 323         if (!info.dev || !nft_flowtable_find_dev(info.dev, ft))
 324                 return;
 325
 326         route->tuple[!dir].in.ifindex = info.dev->ifindex;
 327 +
 328 +       if (info.xmit_type == FLOW_OFFLOAD_XMIT_DIRECT) {
 329 +               memcpy(route->tuple[dir].out.h_source, info.h_source, ETH_ALEN);
 330 +               memcpy(route->tuple[dir].out.h_dest, info.h_dest, ETH_ALEN);
 331 +               route->tuple[dir].out.ifindex = info.dev->ifindex;
 332 +               route->tuple[dir].xmit_type = info.xmit_type;
 333 +       }
 334  }
 335
 336  static int nft_flow_route(const struct nft_pktinfo *pkt,