Following the TCP socket lookup changes, allow selecting the receiving socket from BPF before searching for bound socket by destination address and port.
As connected and bound but non-connected socket lookup currently happens in one step, we split the lookup in two phases to run BPF only after a lookup for a connected socket was a miss. Hence making sure connected UDP sockets continue to work as expected in presence of a BPF inet_lookup program. Suggested-by: Marek Majkowski <[email protected]> Reviewed-by: Lorenz Bauer <[email protected]> Signed-off-by: Jakub Sitnicki <[email protected]> --- net/ipv4/udp.c | 44 ++++++++++++++++++++++++++++++++------------ 1 file changed, 32 insertions(+), 12 deletions(-) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 9fffe9e9eec6..3a4b98f89249 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -353,7 +353,7 @@ int udp_v4_get_port(struct sock *sk, unsigned short snum) static int compute_score(struct sock *sk, struct net *net, __be32 saddr, __be16 sport, __be32 daddr, unsigned short hnum, - int dif, int sdif) + int dif, int sdif, unsigned char state) { int score; struct inet_sock *inet; @@ -364,6 +364,9 @@ static int compute_score(struct sock *sk, struct net *net, ipv6_only_sock(sk)) return -1; + if (state && sk->sk_state != state) + return -1; + if (sk->sk_rcv_saddr != daddr) return -1; @@ -411,7 +414,8 @@ static struct sock *udp4_lib_lookup2(struct net *net, __be32 daddr, unsigned int hnum, int dif, int sdif, struct udp_hslot *hslot2, - struct sk_buff *skb) + struct sk_buff *skb, + unsigned char state) { struct sock *sk, *result; int score, badness; @@ -421,7 +425,7 @@ static struct sock *udp4_lib_lookup2(struct net *net, badness = 0; udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) { score = compute_score(sk, net, saddr, sport, - daddr, hnum, dif, sdif); + daddr, hnum, dif, sdif, state); if (score > badness) { if (sk->sk_reuseport) { hash = udp_ehashfn(net, daddr, hnum, @@ -454,18 +458,34 @@ struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, slot2 = hash2 & udptable->mask; hslot2 = &udptable->hash2[slot2]; + /* Lookup connected sockets */ result = udp4_lib_lookup2(net, saddr, sport, daddr, hnum, dif, sdif, - hslot2, skb); - if (!result) { - hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum); - slot2 = hash2 & udptable->mask; - hslot2 = &udptable->hash2[slot2]; + hslot2, skb, TCP_ESTABLISHED); + if (result) + goto done; - result = udp4_lib_lookup2(net, saddr, sport, - htonl(INADDR_ANY), hnum, dif, sdif, - hslot2, skb); - } + /* Lookup redirect from BPF */ + result = inet_lookup_run_bpf(net, udptable->protocol, + saddr, sport, daddr, hnum); + if (result) + goto done; + + /* Lookup bound sockets */ + result = udp4_lib_lookup2(net, saddr, sport, + daddr, hnum, dif, sdif, + hslot2, skb, 0); + if (result) + goto done; + + hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum); + slot2 = hash2 & udptable->mask; + hslot2 = &udptable->hash2[slot2]; + + result = udp4_lib_lookup2(net, saddr, sport, + htonl(INADDR_ANY), hnum, dif, sdif, + hslot2, skb, 0); +done: if (IS_ERR(result)) return NULL; return result; -- 2.20.1
