From: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
Introduce bpf_xdp_ct_alloc, bpf_skb_ct_alloc and bpf_ct_insert_entry
kfuncs in order to insert a new entry from XDP and TC programs.
Introduce bpf_nf_ct_tuple_parse utility routine to consolidate common
code.
We extract out a helper __nf_ct_set_timeout, used by the ctnetlink and
nf_conntrack_bpf code, extract it out to nf_conntrack_core, so that
nf_conntrack_bpf doesn't need a dependency on CONFIG_NF_CT_NETLINK.
Later this helper will be reused as a helper to set timeout of allocated
but not yet inserted CT entry.
The allocation functions return struct nf_conn___init instead of
nf_conn, to distinguish allocated CT from an already inserted or looked
up CT. This is later used to enforce restrictions on what kfuncs
allocated CT can be used with.
Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
---
include/net/netfilter/nf_conntrack_core.h | 15 ++
net/netfilter/nf_conntrack_bpf.c | 208 +++++++++++++++++++---
net/netfilter/nf_conntrack_netlink.c | 8 +-
3 files changed, 204 insertions(+), 27 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack_core.h b/include/net/netfilter/nf_conntrack_core.h
index 37866c8386e2..83a60c684e6c 100644
--- a/include/net/netfilter/nf_conntrack_core.h
+++ b/include/net/netfilter/nf_conntrack_core.h
@@ -84,4 +84,19 @@ void nf_conntrack_lock(spinlock_t *lock);
extern spinlock_t nf_conntrack_expect_lock;
+/* ctnetlink code shared by both ctnetlink and nf_conntrack_bpf */
+
+#if (IS_BUILTIN(CONFIG_NF_CONNTRACK) && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) || \
+ (IS_MODULE(CONFIG_NF_CONNTRACK) && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES) || \
+ IS_ENABLED(CONFIG_NF_CT_NETLINK))
+
+static inline void __nf_ct_set_timeout(struct nf_conn *ct, u64 timeout)
+{
+ if (timeout > INT_MAX)
+ timeout = INT_MAX;
+ WRITE_ONCE(ct->timeout, nfct_time_stamp + (u32)timeout);
+}
+
+#endif
+
#endif /* _NF_CONNTRACK_CORE_H */
diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c
index 0ba3cbde72ec..6c43160ff036 100644
--- a/net/netfilter/nf_conntrack_bpf.c
+++ b/net/netfilter/nf_conntrack_bpf.c
@@ -55,6 +55,94 @@ enum {
NF_BPF_CT_OPTS_SZ = 12,
};
+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)
+{
+ 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 -EPROTO;
+
+ memset(tuple, 0, sizeof(*tuple));
+
+ switch (tuple_len) {
+ case sizeof(bpf_tuple->ipv4):
+ 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(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 -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, struct bpf_ct_opts *opts, u32 opts_len,
+ u32 timeout)
+{
+ struct nf_conntrack_tuple otuple, rtuple;
+ struct nf_conn *ct;
+ int err;
+
+ if (!opts || !bpf_tuple || opts->reserved[0] || opts->reserved[1] ||
+ opts_len != NF_BPF_CT_OPTS_SZ)
+ return ERR_PTR(-EINVAL);
+
+ if (unlikely(opts->netns_id < BPF_F_CURRENT_NETNS))
+ return ERR_PTR(-EINVAL);
+
+ err = bpf_nf_ct_tuple_parse(bpf_tuple, tuple_len, opts->l4proto,
+ IP_CT_DIR_ORIGINAL, &otuple);
+ if (err < 0)
+ return ERR_PTR(err);
+
+ err = bpf_nf_ct_tuple_parse(bpf_tuple, tuple_len, opts->l4proto,
+ IP_CT_DIR_REPLY, &rtuple);
+ if (err < 0)
+ return ERR_PTR(err);
+
+ if (opts->netns_id >= 0) {
+ net = get_net_ns_by_id(net, opts->netns_id);
+ if (unlikely(!net))
+ return ERR_PTR(-ENONET);
+ }
+
+ 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));
+ __nf_ct_set_timeout(ct, timeout * HZ);
+ ct->status |= IPS_CONFIRMED;
+
+out:
+ if (opts->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, struct bpf_ct_opts *opts,
@@ -63,6 +151,7 @@ static struct nf_conn *__bpf_nf_ct_lookup(struct net *net,
struct nf_conntrack_tuple_hash *hash;
struct nf_conntrack_tuple tuple;
struct nf_conn *ct;
+ int err;
if (!opts || !bpf_tuple || opts->reserved[0] || opts->reserved[1] ||
opts_len != NF_BPF_CT_OPTS_SZ)
@@ -72,27 +161,10 @@ static struct nf_conn *__bpf_nf_ct_lookup(struct net *net,
if (unlikely(opts->netns_id < BPF_F_CURRENT_NETNS))
return ERR_PTR(-EINVAL);
- 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;
- 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;
- break;
- default:
- return ERR_PTR(-EAFNOSUPPORT);
- }
-
- tuple.dst.protonum = opts->l4proto;
+ err = bpf_nf_ct_tuple_parse(bpf_tuple, tuple_len, opts->l4proto,
+ IP_CT_DIR_ORIGINAL, &tuple);
+ if (err < 0)
+ return ERR_PTR(err);
if (opts->netns_id >= 0) {
net = get_net_ns_by_id(net, opts->netns_id);
@@ -116,6 +188,43 @@ __diag_push();
__diag_ignore_all("-Wmissing-prototypes",
"Global functions as their definitions will be in nf_conntrack BTF");
+struct nf_conn___init {
+ struct nf_conn ct;
+};
+
+/* bpf_xdp_ct_alloc - Allocate a new CT entry
+ *
+ * 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 allocation (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___init *
+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;
+
+ nfct = __bpf_nf_ct_alloc_entry(dev_net(ctx->rxq->dev), bpf_tuple, tuple__sz,
+ opts, opts__sz, 10);
+ if (IS_ERR(nfct)) {
+ if (opts)
+ opts->error = PTR_ERR(nfct);
+ return NULL;
+ }
+
+ return (struct nf_conn___init *)nfct;
+}
+
/* bpf_xdp_ct_lookup - Lookup CT entry for the given tuple, and acquire a
* reference to it
*
@@ -150,6 +259,40 @@ bpf_xdp_ct_lookup(struct xdp_md *xdp_ctx, struct bpf_sock_tuple *bpf_tuple,
return nfct;
}
+/* bpf_skb_ct_alloc - Allocate a new CT entry
+ *
+ * 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 allocation (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___init *
+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;
+
+ net = skb->dev ? dev_net(skb->dev) : sock_net(skb->sk);
+ nfct = __bpf_nf_ct_alloc_entry(net, bpf_tuple, tuple__sz, opts, opts__sz, 10);
+ if (IS_ERR(nfct)) {
+ if (opts)
+ opts->error = PTR_ERR(nfct);
+ return NULL;
+ }
+
+ return (struct nf_conn___init *)nfct;
+}
+
/* bpf_skb_ct_lookup - Lookup CT entry for the given tuple, and acquire a
* reference to it
*
@@ -184,6 +327,26 @@ 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___init object, obtained
+ * using bpf_xdp_ct_alloc or bpf_skb_ct_alloc.
+ */
+struct nf_conn *bpf_ct_insert_entry(struct nf_conn___init *nfct__ref)
+{
+ struct nf_conn *nfct = (struct nf_conn *)nfct__ref;
+ int err;
+
+ err = nf_conntrack_hash_check_insert(nfct);
+ if (err < 0) {
+ nf_conntrack_free(nfct);
+ return NULL;
+ }
+ return nfct;
+}
+
/* bpf_ct_release - Release acquired nf_conn object
*
* This must be invoked for referenced PTR_TO_BTF_ID, and the verifier rejects
@@ -204,8 +367,11 @@ void bpf_ct_release(struct nf_conn *nfct)
__diag_pop()
BTF_SET8_START(nf_ct_kfunc_set)
+BTF_ID_FLAGS(func, bpf_xdp_ct_alloc, KF_ACQUIRE, KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_xdp_ct_lookup, KF_ACQUIRE, KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_skb_ct_alloc, KF_ACQUIRE, KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_skb_ct_lookup, KF_ACQUIRE, KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_ct_insert_entry, KF_ACQUIRE, KF_RET_NULL, KF_RELEASE)
BTF_ID_FLAGS(func, bpf_ct_release, KF_RELEASE)
BTF_SET8_END(nf_ct_kfunc_set)
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 722af5e309ba..0729b2f0d44f 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -2025,9 +2025,7 @@ static int ctnetlink_change_timeout(struct nf_conn *ct,
{
u64 timeout = (u64)ntohl(nla_get_be32(cda[CTA_TIMEOUT])) * HZ;
- if (timeout > INT_MAX)
- timeout = INT_MAX;
- WRITE_ONCE(ct->timeout, nfct_time_stamp + (u32)timeout);
+ __nf_ct_set_timeout(ct, timeout);
if (test_bit(IPS_DYING_BIT, &ct->status))
return -ETIME;
@@ -2292,9 +2290,7 @@ ctnetlink_create_conntrack(struct net *net,
goto err1;
timeout = (u64)ntohl(nla_get_be32(cda[CTA_TIMEOUT])) * HZ;
- if (timeout > INT_MAX)
- timeout = INT_MAX;
- ct->timeout = (u32)timeout + nfct_time_stamp;
+ __nf_ct_set_timeout(ct, timeout);
rcu_read_lock();
if (cda[CTA_HELP]) {
--
2.34.1
