Message ID | 1433650677.29864.26.camel@edumazet-glaptop2.roam.corp.google.com |
---|---|
State | Accepted, archived |
Delegated to: | David Miller |
Headers | show |
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Sat, 06 Jun 2015 21:17:57 -0700 > From: Eric Dumazet <edumazet@google.com> > > When an application needs to force a source IP on an active TCP socket > it has to use bind(IP, port=x). > > As most applications do not want to deal with already used ports, x is > often set to 0, meaning the kernel is in charge to find an available > port. > But kernel does not know yet if this socket is going to be a listener or > be connected. > It has very limited choices (no full knowledge of final 4-tuple for a > connect()) > > With limited ephemeral port range (about 32K ports), it is very easy to > fill the space. > > This patch adds a new SOL_IP socket option, asking kernel to ignore > the 0 port provided by application in bind(IP, port=0) and only > remember the given IP address. > > The port will be automatically chosen at connect() time, in a way > that allows sharing a source port as long as the 4-tuples are unique. > > This new feature is available for both IPv4 and IPv6 (Thanks Neal) > > Tested: ... > Signed-off-by: Eric Dumazet <edumazet@google.com> Looks good, applied, thanks Eric. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index b6c3737da4e9..47eb67b08abd 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -187,6 +187,7 @@ struct inet_sock { transparent:1, mc_all:1, nodefrag:1; + __u8 bind_address_no_port:1; __u8 rcv_tos; __u8 convert_csum; int uc_index; diff --git a/include/uapi/linux/in.h b/include/uapi/linux/in.h index 641338bef651..83d6236a2f08 100644 --- a/include/uapi/linux/in.h +++ b/include/uapi/linux/in.h @@ -112,6 +112,7 @@ struct in_addr { #define IP_MINTTL 21 #define IP_NODEFRAG 22 #define IP_CHECKSUM 23 +#define IP_BIND_ADDRESS_NO_PORT 24 /* IP_MTU_DISCOVER values */ #define IP_PMTUDISC_DONT 0 /* Never send DF frames */ diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 6ad0f7a711c9..cc858ef44451 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -488,7 +488,8 @@ int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) inet->inet_saddr = 0; /* Use device */ /* Make sure we are allowed to bind here. */ - if (sk->sk_prot->get_port(sk, snum)) { + if ((snum || !inet->bind_address_no_port) && + sk->sk_prot->get_port(sk, snum)) { inet->inet_saddr = inet->inet_rcv_saddr = 0; err = -EADDRINUSE; goto out_release_sock; diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index 7cfb0893f263..04ae2992a5cd 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -582,6 +582,7 @@ static int do_ip_setsockopt(struct sock *sk, int level, case IP_TRANSPARENT: case IP_MINTTL: case IP_NODEFRAG: + case IP_BIND_ADDRESS_NO_PORT: case IP_UNICAST_IF: case IP_MULTICAST_TTL: case IP_MULTICAST_ALL: @@ -732,6 +733,9 @@ static int do_ip_setsockopt(struct sock *sk, int level, } inet->nodefrag = val ? 1 : 0; break; + case IP_BIND_ADDRESS_NO_PORT: + inet->bind_address_no_port = val ? 1 : 0; + break; case IP_MTU_DISCOVER: if (val < IP_PMTUDISC_DONT || val > IP_PMTUDISC_OMIT) goto e_inval; @@ -1324,6 +1328,9 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname, case IP_NODEFRAG: val = inet->nodefrag; break; + case IP_BIND_ADDRESS_NO_PORT: + val = inet->bind_address_no_port; + break; case IP_MTU_DISCOVER: val = inet->pmtudisc; break; diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index f3866c0b6cfe..7de52b65173f 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -362,7 +362,8 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) np->saddr = addr->sin6_addr; /* Make sure we are allowed to bind here. */ - if (sk->sk_prot->get_port(sk, snum)) { + if ((snum || !inet->bind_address_no_port) && + sk->sk_prot->get_port(sk, snum)) { inet_reset_saddr(sk); err = -EADDRINUSE; goto out;