Xdp tunnel 7674 v6.8

doc/userguide/configuration/suricata-yaml.rst

@@ -3025,6 +3025,30 @@ default.
 Using this default setting, flows will be associated only if the compared packet
 headers are encapsulated in the same number of headers.
 
+Tunnels
+~~~~~~~
+
+If your packets sources are multiple tunnels encapsulating the traffic,
+you can configure the ``decoder.tunnels`` section to assign a tunnel
+identifier to each of these tunnels.
+
+These tunnel identifiers are used in flow hashing to be able to distinguish
+the same-looking flow (same 5-tuple) from different tunnels, meaning it
+is in fact a different subnetwork (like a VLAN identifier).
+
+This section is a list of tunnels with the following parameters:
+::
+
+    - id: 1
+      type: erspan2 # or vxlan
+      src: 192.168.1.1
+      dst: 192.168.1.3
+      session: 123 # erspan span id or vxlan vni
+
+It is also recommended to define ``decoder.tunnels-ifaces`` list of interfaces
+receiving tunneled traffic. The traffic received on these interfaces that do
+not belong to a defined tunnel will be skipped.
+
 Advanced Options
 ----------------
 

ebpf/xdp_filter.c

@@ -23,6 +23,10 @@
 #include <linux/if_ether.h>
 #include <linux/if_packet.h>
 #include <linux/if_vlan.h>
+/* Workaround to avoid the need of 32bit headers */
+#define _LINUX_IF_H
+#define IFNAMSIZ 16
+#include <linux/if_tunnel.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/tcp.h>
@@ -61,11 +65,21 @@
  * also be used as workaround of some hardware offload issue */
 #define VLAN_TRACKING    1
 
+/* vxlan port configurable */
+#define VXLAN_PORT 4789
+
 struct vlan_hdr {
     __u16	h_vlan_TCI;
     __u16	h_vlan_encapsulated_proto;
 };
 
+struct flowtunnel_keys {
+    __u32 src;
+    __u32 dst;
+    __u32 session : 24;
+    __u8 tunnel : 8;
+};
+
 struct flowv4_keys {
     __u32 src;
     __u32 dst;
@@ -75,7 +89,8 @@ struct flowv4_keys {
     };
     __u8 ip_proto:1;
     __u16 vlan0:15;
-    __u16 vlan1;
+    __u8 tunnel : 1;
+    __u16 vlan1_or_tunnel_id : 15;
 };
 
 struct flowv6_keys {
@@ -87,14 +102,30 @@ struct flowv6_keys {
     };
     __u8 ip_proto:1;
     __u16 vlan0:15;
-    __u16 vlan1;
+    __u8 tunnel : 1;
+    __u16 vlan1_or_tunnel_id : 15;
 };
 
 struct pair {
     __u64 packets;
     __u64 bytes;
 };
 
+struct flowtunnel_id {
+    __u16 tunnel_id;
+};
+
+struct {
+#if USE_PERCPU_HASH
+    __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
+#else
+    __uint(type, BPF_MAP_TYPE_HASH);
+#endif
+    __type(key, struct flowtunnel_keys);
+    __type(value, struct flowtunnel_id);
+    __uint(max_entries, 256);
+} flow_table_tunnels SEC(".maps");
+
 struct {
 #if USE_PERCPU_HASH
     __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
@@ -232,7 +263,8 @@ static __always_inline int get_dport(void *trans_data, void *data_end,
     }
 }
 
-static int __always_inline filter_ipv4(struct xdp_md *ctx, void *data, __u64 nh_off, void *data_end, __u16 vlan0, __u16 vlan1)
+static int __always_inline filter_ipv4_final(
+        struct xdp_md *ctx, void *data, __u64 nh_off, void *data_end, __u16 vlan0, __u16 vlan1)
 {
     struct iphdr *iph = data + nh_off;
     int dport;
@@ -280,7 +312,8 @@ static int __always_inline filter_ipv4(struct xdp_md *ctx, void *data, __u64 nh_
     tuple.port16[1] = (__u16)dport;
 
     tuple.vlan0 = vlan0;
-    tuple.vlan1 = vlan1;
+    tuple.tunnel = (vlan1 & 0x8000) != 0;
+    tuple.vlan1_or_tunnel_id = vlan1 & 0x7FFF;
 
     value = bpf_map_lookup_elem(&flow_table_v4, &tuple);
 #if 0
@@ -421,7 +454,8 @@ static int __always_inline filter_ipv6(struct xdp_md *ctx, void *data, __u64 nh_
     tuple.port16[1] = dport;
 
     tuple.vlan0 = vlan0;
-    tuple.vlan1 = vlan1;
+    tuple.tunnel = (vlan1 & 0x8000) != 0;
+    tuple.vlan1_or_tunnel_id = vlan1 & 0x7FFF;
 
     value = bpf_map_lookup_elem(&flow_table_v6, &tuple);
     if (value) {
@@ -482,6 +516,219 @@ static int __always_inline filter_ipv6(struct xdp_md *ctx, void *data, __u64 nh_
 #endif
 }
 
+static int __always_inline filter_erspan(
+        struct xdp_md *ctx, void *data, __u64 nh_off, void *data_end, struct iphdr *iph)
+{
+    struct erspan_hdr {
+        __be16 ver_vlan;
+        __be16 flags_spanid;
+        __be32 padding;
+    };
+    __u16 vlan0 = 0;
+    __u16 vlan1 = 0;
+    struct flowtunnel_keys tuple;
+    __u16 h_proto;
+    __u16 flags_spanid;
+    struct flowtunnel_id *value;
+
+    struct erspan_hdr *erhdr = (struct erspan_hdr *)(data + nh_off);
+    if ((void *)(erhdr + 1) > data_end)
+        return XDP_PASS;
+
+    if ((erhdr->ver_vlan & 0xF0) != 0x10) {
+        // only handle ERSPAN 2
+        return XDP_PASS;
+    }
+    flags_spanid = erhdr->flags_spanid;
+    if ((flags_spanid & 0x1800) == 0x800) {
+        // do not handle ISL encapsulated
+        return XDP_PASS;
+    }
+
+    tuple.tunnel = 4; // DECODE_TUNNEL_ERSPANII
+    tuple.src = iph->saddr;
+    tuple.dst = iph->daddr;
+    tuple.session = flags_spanid & 0x3FF;
+    value = bpf_map_lookup_elem(&flow_table_tunnels, &tuple);
+    if (!value) {
+        // unknown tunnel
+        return XDP_PASS;
+    }
+    vlan1 = 0x8000 | value->tunnel_id;
+
+    nh_off += 8;
+    if (data + nh_off + sizeof(struct ethhdr) > data_end)
+        return XDP_PASS;
+
+    struct ethhdr *eth = data + nh_off;
+    nh_off += sizeof(*eth);
+
+    h_proto = eth->h_proto;
+
+#if VLAN_TRACKING
+    if ((flags_spanid & 0x1800) == 0x1000) {
+        vlan0 = erhdr->ver_vlan & 0xFFF;
+    }
+#endif
+    if ((flags_spanid & 0x1800) == 0x1800 && (h_proto == __constant_htons(ETH_P_8021Q) ||
+                                                     h_proto == __constant_htons(ETH_P_8021AD))) {
+        struct vlan_hdr *vhdr;
+
+        if (data + nh_off + sizeof(struct vlan_hdr) > data_end)
+            return XDP_PASS;
+        vhdr = data + nh_off;
+        nh_off += sizeof(struct vlan_hdr);
+        h_proto = vhdr->h_vlan_encapsulated_proto;
+#if VLAN_TRACKING
+        vlan0 = vhdr->h_vlan_TCI & 0x0fff;
+#endif
+    }
+    if (h_proto == __constant_htons(ETH_P_IP))
+        return filter_ipv4_final(ctx, data, nh_off, data_end, vlan0, vlan1);
+    else if (h_proto == __constant_htons(ETH_P_IPV6))
+        return filter_ipv6(ctx, data, nh_off, data_end, vlan0, vlan1);
+    return XDP_PASS;
+}
+
+static int __always_inline filter_gre(
+        struct xdp_md *ctx, void *data, __u64 nh_off, void *data_end, struct iphdr *iph)
+{
+    struct gre_hdr {
+        __be16 flags;
+        __be16 proto;
+    };
+    __u16 proto;
+
+    struct gre_hdr *grhdr = (struct gre_hdr *)(data + nh_off);
+
+    if ((void *)(grhdr + 1) > data_end)
+        return XDP_PASS;
+
+    // only GRE version 0 without routing
+    if (grhdr->flags & (GRE_VERSION | GRE_ROUTING))
+        return XDP_PASS;
+
+    nh_off += 4;
+    if (grhdr->flags & GRE_CSUM)
+        nh_off += 4;
+    if (grhdr->flags & GRE_KEY)
+        nh_off += 4;
+    if (grhdr->flags & GRE_SEQ)
+        nh_off += 4;
+    if (data + nh_off > data_end)
+        return XDP_PASS;
+
+    proto = grhdr->proto;
+    // only handle erspan over gre
+    if (proto == __constant_htons(ETH_P_ERSPAN)) {
+        return filter_erspan(ctx, data, nh_off, data_end, iph);
+    }
+    return XDP_PASS;
+}
+
+struct vxlanhdr {
+    __be16 flags;
+    __be16 gdp;
+    __u8 vni0;
+    __u8 vni1;
+    __u8 vni2;
+    __u8 res;
+};
+
+static int __always_inline filter_vxlan(
+        struct xdp_md *ctx, void *data, __u64 nh_off, void *data_end, struct iphdr *iph)
+{
+    __u16 vlan0 = 0;
+    __u16 vlan1;
+    __u16 h_proto;
+    struct flowtunnel_keys tuple;
+    struct flowtunnel_id *value;
+
+    struct vxlanhdr *vh = (struct vxlanhdr *)(data + nh_off);
+
+    tuple.tunnel = 6; // DECODE_TUNNEL_VXLAN
+    tuple.src = iph->saddr;
+    tuple.dst = iph->daddr;
+    tuple.session = vh->vni2 | (vh->vni1 << 8) | (vh->vni0 << 16);
+    value = bpf_map_lookup_elem(&flow_table_tunnels, &tuple);
+    if (!value) {
+        // unknown tunnel
+        return XDP_PASS;
+    }
+    vlan1 = 0x8000 | value->tunnel_id;
+    nh_off += sizeof(*vh);
+
+    struct ethhdr *eth = data + nh_off;
+    nh_off += sizeof(*eth);
+    h_proto = eth->h_proto;
+
+    if (h_proto == __constant_htons(ETH_P_8021Q) || h_proto == __constant_htons(ETH_P_8021AD)) {
+        struct vlan_hdr *vhdr;
+
+        if (data + nh_off + sizeof(struct vlan_hdr) > data_end)
+            return XDP_PASS;
+        vhdr = data + nh_off;
+        nh_off += sizeof(struct vlan_hdr);
+        h_proto = vhdr->h_vlan_encapsulated_proto;
+#if VLAN_TRACKING
+        vlan0 = vhdr->h_vlan_TCI & 0x0fff;
+#endif
+    }
+
+    if (h_proto == __constant_htons(ETH_P_IP))
+        return filter_ipv4_final(ctx, data, nh_off, data_end, vlan0, vlan1);
+    else if (h_proto == __constant_htons(ETH_P_IPV6))
+        return filter_ipv6(ctx, data, nh_off, data_end, vlan0, vlan1);
+    return XDP_PASS;
+}
+
+static int __always_inline is_vxlan(void *data, __u64 nh_off, void *data_end)
+{
+    if (data + nh_off + sizeof(struct iphdr) + sizeof(struct udphdr) + sizeof(struct vxlanhdr) +
+                    sizeof(struct ethhdr) >
+            data_end) {
+        return 0;
+    }
+    struct udphdr *uh = (struct udphdr *)(data + nh_off + sizeof(struct iphdr));
+    if (uh->dest != __constant_ntohs(VXLAN_PORT)) {
+        return 0;
+    }
+    struct vxlanhdr *vh =
+            (struct vxlanhdr *)(data + nh_off + sizeof(struct iphdr) + sizeof(struct udphdr));
+    // check vni is present and reserved is 0
+    if ((vh->flags & 0xDEFF) == 8 && vh->res == 0) {
+        return 0;
+    }
+    // check ethernet type is handled
+    struct ethhdr *eth = (struct ethhdr *)(data + nh_off + sizeof(struct iphdr) +
+                                           sizeof(struct udphdr) + sizeof(struct vxlanhdr));
+    if (eth->h_proto == __constant_htons(ETH_P_8021Q) ||
+            eth->h_proto == __constant_htons(ETH_P_8021AD) ||
+            eth->h_proto == __constant_htons(ETH_P_IP) ||
+            eth->h_proto == __constant_htons(ETH_P_IPV6)) {
+        return 1;
+    }
+
+    return 0;
+}
+
+static int __always_inline filter_ipv4(
+        struct xdp_md *ctx, void *data, __u64 nh_off, void *data_end, __u16 vlan0, __u16 vlan1)
+{
+    struct iphdr *iph = data + nh_off;
+    if ((void *)(iph + 1) > data_end)
+        return XDP_PASS;
+
+    if (iph->protocol == IPPROTO_GRE) {
+        nh_off += sizeof(struct iphdr);
+        return filter_gre(ctx, data, nh_off, data_end, iph);
+    } else if (iph->protocol == IPPROTO_UDP && is_vxlan(data, nh_off, data_end)) {
+        nh_off += sizeof(struct iphdr) + sizeof(struct udphdr);
+        return filter_vxlan(ctx, data, nh_off, data_end, iph);
+    }
+    return filter_ipv4_final(ctx, data, nh_off, data_end, vlan0, vlan1);
+}
+
 int SEC("xdp") xdp_hashfilter(struct xdp_md *ctx)
 {
     void *data_end = (void *)(long)ctx->data_end;

etc/schema.json

@@ -7839,9 +7839,17 @@
                 },
                 "src_port": {
                     "type": "integer"
+                },
+                "tunnel_id": {
+                    "type": "integer",
+                    "description": "If any, the tunnel identifier defined in suricata.yaml decoder.tunnels section"
                 }
             }
         },
+        "tunnel_id": {
+            "type": "integer",
+            "description": "if any, the tunnel identifier defined in suricata.yaml decoder.tunnels section"
+        },
         "tx_guessed": {
             "type": "boolean",
             "description":