Introduce bpf_xdp_ct_alloc, bpf_skb_ct_alloc and bpf_ct_insert_entry
kfunc helpers in order to add a new entry to ct map from an ebpf program.
Introduce bpf_nf_ct_tuple_parse utility routine.
Acked-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
---
net/netfilter/nf_conntrack_bpf.c | 249 ++++++++++++++++++++++++++++---
1 file changed, 226 insertions(+), 23 deletions(-)
diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c
index c50f4c1e5b3a..70731b57b2d4 100644
--- a/net/netfilter/nf_conntrack_bpf.c
+++ b/net/netfilter/nf_conntrack_bpf.c
@@ -57,41 +57,106 @@ enum {
NF_BPF_CT_OPTS_SZ = 12,
};
-static struct nf_conn *__bpf_nf_ct_lookup(struct net *net,
- struct bpf_sock_tuple *bpf_tuple,
- u32 tuple_len, u8 protonum,
- s32 netns_id, u8 *dir)
+static int bpf_nf_ct_tuple_parse(struct bpf_sock_tuple *bpf_tuple,
+ u32 tuple_len, u8 protonum, u8 dir,
+ struct nf_conntrack_tuple *tuple)
{
- struct nf_conntrack_tuple_hash *hash;
- struct nf_conntrack_tuple tuple;
- struct nf_conn *ct;
+ union nf_inet_addr *src = dir ? &tuple->dst.u3 : &tuple->src.u3;
+ union nf_inet_addr *dst = dir ? &tuple->src.u3 : &tuple->dst.u3;
+ union nf_conntrack_man_proto *sport = dir ? (void *)&tuple->dst.u
+ : &tuple->src.u;
+ union nf_conntrack_man_proto *dport = dir ? &tuple->src.u
+ : (void *)&tuple->dst.u;
if (unlikely(protonum != IPPROTO_TCP && protonum != IPPROTO_UDP))
- return ERR_PTR(-EPROTO);
- if (unlikely(netns_id < BPF_F_CURRENT_NETNS))
- return ERR_PTR(-EINVAL);
+ return -EPROTO;
+
+ memset(tuple, 0, sizeof(*tuple));
- memset(&tuple, 0, sizeof(tuple));
switch (tuple_len) {
case sizeof(bpf_tuple->ipv4):
- tuple.src.l3num = AF_INET;
- tuple.src.u3.ip = bpf_tuple->ipv4.saddr;
- tuple.src.u.tcp.port = bpf_tuple->ipv4.sport;
- tuple.dst.u3.ip = bpf_tuple->ipv4.daddr;
- tuple.dst.u.tcp.port = bpf_tuple->ipv4.dport;
+ tuple->src.l3num = AF_INET;
+ src->ip = bpf_tuple->ipv4.saddr;
+ sport->tcp.port = bpf_tuple->ipv4.sport;
+ dst->ip = bpf_tuple->ipv4.daddr;
+ dport->tcp.port = bpf_tuple->ipv4.dport;
break;
case sizeof(bpf_tuple->ipv6):
- tuple.src.l3num = AF_INET6;
- memcpy(tuple.src.u3.ip6, bpf_tuple->ipv6.saddr, sizeof(bpf_tuple->ipv6.saddr));
- tuple.src.u.tcp.port = bpf_tuple->ipv6.sport;
- memcpy(tuple.dst.u3.ip6, bpf_tuple->ipv6.daddr, sizeof(bpf_tuple->ipv6.daddr));
- tuple.dst.u.tcp.port = bpf_tuple->ipv6.dport;
+ tuple->src.l3num = AF_INET6;
+ memcpy(src->ip6, bpf_tuple->ipv6.saddr, sizeof(bpf_tuple->ipv6.saddr));
+ sport->tcp.port = bpf_tuple->ipv6.sport;
+ memcpy(dst->ip6, bpf_tuple->ipv6.daddr, sizeof(bpf_tuple->ipv6.daddr));
+ dport->tcp.port = bpf_tuple->ipv6.dport;
break;
default:
- return ERR_PTR(-EAFNOSUPPORT);
+ return -EAFNOSUPPORT;
+ }
+ tuple->dst.protonum = protonum;
+ tuple->dst.dir = dir;
+
+ return 0;
+}
+
+static struct nf_conn *
+__bpf_nf_ct_alloc_entry(struct net *net, struct bpf_sock_tuple *bpf_tuple,
+ u32 tuple_len, u8 protonum, s32 netns_id, u32 timeout)
+{
+ struct nf_conntrack_tuple otuple, rtuple;
+ struct nf_conn *ct;
+ int err;
+
+ if (unlikely(netns_id < BPF_F_CURRENT_NETNS))
+ return ERR_PTR(-EINVAL);
+
+ err = bpf_nf_ct_tuple_parse(bpf_tuple, tuple_len, protonum,
+ IP_CT_DIR_ORIGINAL, &otuple);
+ if (err < 0)
+ return ERR_PTR(err);
+
+ err = bpf_nf_ct_tuple_parse(bpf_tuple, tuple_len, protonum,
+ IP_CT_DIR_REPLY, &rtuple);
+ if (err < 0)
+ return ERR_PTR(err);
+
+ if (netns_id >= 0) {
+ net = get_net_ns_by_id(net, netns_id);
+ if (unlikely(!net))
+ return ERR_PTR(-ENONET);
}
- tuple.dst.protonum = protonum;
+ ct = nf_conntrack_alloc(net, &nf_ct_zone_dflt, &otuple, &rtuple,
+ GFP_ATOMIC);
+ if (IS_ERR(ct))
+ goto out;
+
+ memset(&ct->proto, 0, sizeof(ct->proto));
+ ct->timeout = timeout * HZ + jiffies;
+ ct->status |= IPS_CONFIRMED;
+
+out:
+ if (netns_id >= 0)
+ put_net(net);
+
+ return ct;
+}
+
+static struct nf_conn *__bpf_nf_ct_lookup(struct net *net,
+ struct bpf_sock_tuple *bpf_tuple,
+ u32 tuple_len, u8 protonum,
+ s32 netns_id, u8 *dir)
+{
+ struct nf_conntrack_tuple_hash *hash;
+ struct nf_conntrack_tuple tuple;
+ struct nf_conn *ct;
+ int err;
+
+ if (unlikely(netns_id < BPF_F_CURRENT_NETNS))
+ return ERR_PTR(-EINVAL);
+
+ err = bpf_nf_ct_tuple_parse(bpf_tuple, tuple_len, protonum,
+ IP_CT_DIR_ORIGINAL, &tuple);
+ if (err < 0)
+ return ERR_PTR(err);
if (netns_id >= 0) {
net = get_net_ns_by_id(net, netns_id);
@@ -116,6 +181,49 @@ __diag_push();
__diag_ignore_all("-Wmissing-prototypes",
"Global functions as their definitions will be in nf_conntrack BTF");
+/* bpf_xdp_ct_alloc - Alloc a new CT entry for the given tuple
+ *
+ * Parameters:
+ * @xdp_ctx - Pointer to ctx (xdp_md) in XDP program
+ * Cannot be NULL
+ * @bpf_tuple - Pointer to memory representing the tuple to look up
+ * Cannot be NULL
+ * @tuple__sz - Length of the tuple structure
+ * Must be one of sizeof(bpf_tuple->ipv4) or
+ * sizeof(bpf_tuple->ipv6)
+ * @opts - Additional options for lookup (documented above)
+ * Cannot be NULL
+ * @opts__sz - Length of the bpf_ct_opts structure
+ * Must be NF_BPF_CT_OPTS_SZ (12)
+ */
+struct nf_conn *
+bpf_xdp_ct_alloc(struct xdp_md *xdp_ctx, struct bpf_sock_tuple *bpf_tuple,
+ u32 tuple__sz, struct bpf_ct_opts *opts, u32 opts__sz)
+{
+ struct xdp_buff *ctx = (struct xdp_buff *)xdp_ctx;
+ struct nf_conn *nfct;
+
+ BUILD_BUG_ON(sizeof(struct bpf_ct_opts) != NF_BPF_CT_OPTS_SZ);
+ if (!opts)
+ return NULL;
+
+ if (!bpf_tuple || opts->reserved[0] || opts->reserved[1] ||
+ opts__sz != NF_BPF_CT_OPTS_SZ) {
+ opts->error = -EINVAL;
+ return NULL;
+ }
+
+ nfct = __bpf_nf_ct_alloc_entry(dev_net(ctx->rxq->dev), bpf_tuple,
+ tuple__sz, opts->l4proto,
+ opts->netns_id, 10);
+ if (IS_ERR_OR_NULL(nfct)) {
+ opts->error = PTR_ERR(nfct);
+ return NULL;
+ }
+
+ return nfct;
+}
+
/* bpf_xdp_ct_lookup - Lookup CT entry for the given tuple, and acquire a
* reference to it
*
@@ -159,6 +267,50 @@ bpf_xdp_ct_lookup(struct xdp_md *xdp_ctx, struct bpf_sock_tuple *bpf_tuple,
return nfct;
}
+/* bpf_skb_ct_alloc - Alloc a new CT entry for the given tuple
+ *
+ * Parameters:
+ * @skb_ctx - Pointer to ctx (__sk_buff) in TC program
+ * Cannot be NULL
+ * @bpf_tuple - Pointer to memory representing the tuple to look up
+ * Cannot be NULL
+ * @tuple__sz - Length of the tuple structure
+ * Must be one of sizeof(bpf_tuple->ipv4) or
+ * sizeof(bpf_tuple->ipv6)
+ * @opts - Additional options for lookup (documented above)
+ * Cannot be NULL
+ * @opts__sz - Length of the bpf_ct_opts structure
+ * Must be NF_BPF_CT_OPTS_SZ (12)
+ */
+struct nf_conn *
+bpf_skb_ct_alloc(struct __sk_buff *skb_ctx, struct bpf_sock_tuple *bpf_tuple,
+ u32 tuple__sz, struct bpf_ct_opts *opts, u32 opts__sz)
+{
+ struct sk_buff *skb = (struct sk_buff *)skb_ctx;
+ struct nf_conn *nfct;
+ struct net *net;
+
+ BUILD_BUG_ON(sizeof(struct bpf_ct_opts) != NF_BPF_CT_OPTS_SZ);
+ if (!opts)
+ return NULL;
+
+ if (!bpf_tuple || opts->reserved[0] || opts->reserved[1] ||
+ opts__sz != NF_BPF_CT_OPTS_SZ) {
+ opts->error = -EINVAL;
+ return NULL;
+ }
+
+ net = skb->dev ? dev_net(skb->dev) : sock_net(skb->sk);
+ nfct = __bpf_nf_ct_alloc_entry(net, bpf_tuple, tuple__sz,
+ opts->l4proto, opts->netns_id, 10);
+ if (IS_ERR_OR_NULL(nfct)) {
+ opts->error = PTR_ERR(nfct);
+ return NULL;
+ }
+
+ return nfct;
+}
+
/* bpf_skb_ct_lookup - Lookup CT entry for the given tuple, and acquire a
* reference to it
*
@@ -202,6 +354,40 @@ bpf_skb_ct_lookup(struct __sk_buff *skb_ctx, struct bpf_sock_tuple *bpf_tuple,
return nfct;
}
+/* bpf_ct_insert_entry - Add the provided entry into a CT map
+ *
+ * This must be invoked for referenced PTR_TO_BTF_ID.
+ *
+ * @nfct__ref - Pointer to referenced nf_conn object
+ */
+const struct nf_conn *
+bpf_ct_insert_entry(struct nf_conn *nfct__ref, struct bpf_ct_opts *opts,
+ u32 opts__sz)
+{
+ int err;
+
+ BUILD_BUG_ON(sizeof(struct bpf_ct_opts) != NF_BPF_CT_OPTS_SZ);
+
+ if (!nfct__ref)
+ return NULL;
+
+ if (!opts || opts->reserved[0] || opts->reserved[1] ||
+ opts__sz != NF_BPF_CT_OPTS_SZ) {
+ nf_conntrack_free(nfct__ref);
+ opts->error = -EINVAL;
+ return NULL;
+ }
+
+ err = nf_conntrack_hash_check_insert(nfct__ref);
+ if (err < 0) {
+ nf_conntrack_free(nfct__ref);
+ opts->error = err;
+ return NULL;
+ }
+
+ return nfct__ref;
+}
+
/* bpf_ct_release - Release acquired nf_conn object
*
* This must be invoked for referenced PTR_TO_BTF_ID, and the verifier rejects
@@ -243,23 +429,31 @@ void bpf_ct_refresh_timeout(const struct nf_conn *nfct__ref, u32 timeout)
__diag_pop()
BTF_SET_START(nf_ct_xdp_check_kfunc_ids)
+BTF_ID(func, bpf_xdp_ct_alloc)
BTF_ID(func, bpf_xdp_ct_lookup)
+BTF_ID(func, bpf_ct_insert_entry)
BTF_ID(func, bpf_ct_release)
BTF_ID(func, bpf_ct_refresh_timeout);
BTF_SET_END(nf_ct_xdp_check_kfunc_ids)
BTF_SET_START(nf_ct_tc_check_kfunc_ids)
+BTF_ID(func, bpf_skb_ct_alloc)
BTF_ID(func, bpf_skb_ct_lookup)
+BTF_ID(func, bpf_ct_insert_entry)
BTF_ID(func, bpf_ct_release)
BTF_ID(func, bpf_ct_refresh_timeout);
BTF_SET_END(nf_ct_tc_check_kfunc_ids)
BTF_SET_START(nf_ct_acquire_kfunc_ids)
+BTF_ID(func, bpf_xdp_ct_alloc)
BTF_ID(func, bpf_xdp_ct_lookup)
+BTF_ID(func, bpf_skb_ct_alloc)
BTF_ID(func, bpf_skb_ct_lookup)
+BTF_ID(func, bpf_ct_insert_entry)
BTF_SET_END(nf_ct_acquire_kfunc_ids)
BTF_SET_START(nf_ct_release_kfunc_ids)
+BTF_ID(func, bpf_ct_insert_entry)
BTF_ID(func, bpf_ct_release)
BTF_SET_END(nf_ct_release_kfunc_ids)
@@ -267,12 +461,21 @@ BTF_SET_END(nf_ct_release_kfunc_ids)
#define nf_ct_ret_null_kfunc_ids nf_ct_acquire_kfunc_ids
BTF_ID_LIST(nf_ct_acq_rel_pairs)
+BTF_ID(func, bpf_xdp_ct_alloc)
+BTF_ID(func, bpf_ct_insert_entry)
+
+BTF_ID(func, bpf_skb_ct_alloc)
+BTF_ID(func, bpf_ct_insert_entry)
+
BTF_ID(func, bpf_xdp_ct_lookup)
BTF_ID(func, bpf_ct_release)
BTF_ID(func, bpf_skb_ct_lookup)
BTF_ID(func, bpf_ct_release)
+BTF_ID(func, bpf_ct_insert_entry)
+BTF_ID(func, bpf_ct_release)
+
static const struct btf_kfunc_id_set nf_conntrack_xdp_kfunc_set = {
.owner = THIS_MODULE,
.check_set = &nf_ct_xdp_check_kfunc_ids,
--
2.35.3
