inet6: Run SK_LOOKUP BPF program on socket lookup

Following ipv4 stack changes, run a BPF program attached to netns before
looking up a listening socket. Program can return a listening socket to use
as result of socket lookup, fail the lookup, or take no action.

Suggested-by: Marek Majkowski <marek@cloudflare.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200717103536.397595-7-jakub@cloudflare.com
This commit is contained in:
Jakub Sitnicki 2020-07-17 12:35:27 +02:00 committed by Alexei Starovoitov
parent 5df6531292
commit 1122702f02
2 changed files with 74 additions and 0 deletions

View File

@ -1386,4 +1386,43 @@ static inline bool bpf_sk_lookup_run_v4(struct net *net, int protocol,
return no_reuseport;
}
#if IS_ENABLED(CONFIG_IPV6)
static inline bool bpf_sk_lookup_run_v6(struct net *net, int protocol,
const struct in6_addr *saddr,
const __be16 sport,
const struct in6_addr *daddr,
const u16 dport,
struct sock **psk)
{
struct bpf_prog_array *run_array;
struct sock *selected_sk = NULL;
bool no_reuseport = false;
rcu_read_lock();
run_array = rcu_dereference(net->bpf.run_array[NETNS_BPF_SK_LOOKUP]);
if (run_array) {
struct bpf_sk_lookup_kern ctx = {
.family = AF_INET6,
.protocol = protocol,
.v6.saddr = saddr,
.v6.daddr = daddr,
.sport = sport,
.dport = dport,
};
u32 act;
act = BPF_PROG_SK_LOOKUP_RUN_ARRAY(run_array, ctx, BPF_PROG_RUN);
if (act == SK_PASS) {
selected_sk = ctx.selected_sk;
no_reuseport = ctx.no_reuseport;
} else {
selected_sk = ERR_PTR(-ECONNREFUSED);
}
}
rcu_read_unlock();
*psk = selected_sk;
return no_reuseport;
}
#endif /* IS_ENABLED(CONFIG_IPV6) */
#endif /* __LINUX_FILTER_H__ */

View File

@ -21,6 +21,8 @@
#include <net/ip.h>
#include <net/sock_reuseport.h>
extern struct inet_hashinfo tcp_hashinfo;
u32 inet6_ehashfn(const struct net *net,
const struct in6_addr *laddr, const u16 lport,
const struct in6_addr *faddr, const __be16 fport)
@ -159,6 +161,31 @@ static struct sock *inet6_lhash2_lookup(struct net *net,
return result;
}
static inline struct sock *inet6_lookup_run_bpf(struct net *net,
struct inet_hashinfo *hashinfo,
struct sk_buff *skb, int doff,
const struct in6_addr *saddr,
const __be16 sport,
const struct in6_addr *daddr,
const u16 hnum)
{
struct sock *sk, *reuse_sk;
bool no_reuseport;
if (hashinfo != &tcp_hashinfo)
return NULL; /* only TCP is supported */
no_reuseport = bpf_sk_lookup_run_v6(net, IPPROTO_TCP,
saddr, sport, daddr, hnum, &sk);
if (no_reuseport || IS_ERR_OR_NULL(sk))
return sk;
reuse_sk = lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum);
if (reuse_sk)
sk = reuse_sk;
return sk;
}
struct sock *inet6_lookup_listener(struct net *net,
struct inet_hashinfo *hashinfo,
struct sk_buff *skb, int doff,
@ -170,6 +197,14 @@ struct sock *inet6_lookup_listener(struct net *net,
struct sock *result = NULL;
unsigned int hash2;
/* Lookup redirect from BPF */
if (static_branch_unlikely(&bpf_sk_lookup_enabled)) {
result = inet6_lookup_run_bpf(net, hashinfo, skb, doff,
saddr, sport, daddr, hnum);
if (result)
goto done;
}
hash2 = ipv6_portaddr_hash(net, daddr, hnum);
ilb2 = inet_lhash2_bucket(hashinfo, hash2);