7f175ccbc
Denis Vlasenko
2007-08-16
Subject
add comments regarding SO_REUSEADDR
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Commit Diff GitHub →
include/libbb.h+9 -1
| @@ -282,6 +282,13 @@ void xlisten(int s, int backlog); | |
| void xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen); | |
| ssize_t xsendto(int s, const void *buf, size_t len, const struct sockaddr *to, | |
| socklen_t tolen); | |
| + | /* SO_REUSEADDR allows a server to rebind to an address that is already |
| + | * "in use" by old connections to e.g. previous server instance which is |
| + | * killed or crashed. Without it bind will fail until all such connections |
| + | * time out. Linux does not allow multiple live binds on same ip:port |
| + | * regardless of SO_REUSEADDR (unlike some other flavors of Unix). |
| + | * Turn it on before you call bind(). */ |
| + | //TODO: it seems like in Linux this never fails. Change to void, eliminate error checks |
| int setsockopt_reuseaddr(int fd); | |
| int setsockopt_broadcast(int fd); | |
| /* NB: returns port in host byte order */ | |
| @@ -318,6 +325,7 @@ int xsocket_stream(len_and_sockaddr **lsap); | |
| * numeric IP ("N.N.N.N") or numeric IPv6 address, | |
| * and can have ":PORT" suffix (for IPv6 use "[X:X:...:X]:PORT"). | |
| * Only if there is no suffix, port argument is used */ | |
| + | /* NB: these set SO_REUSEADDR before bind */ |
| int create_and_bind_stream_or_die(const char *bindaddr, int port); | |
| int create_and_bind_dgram_or_die(const char *bindaddr, int port); | |
| /* Create client TCP socket connected to peer:port. Peer cannot be NULL. | |
| @@ -345,7 +353,7 @@ len_and_sockaddr* xhost_and_af2sockaddr(const char *host, int port, sa_family_t | |
| #define host_and_af2sockaddr(host, port, af) ((void)(af), host2sockaddr((host), (port))) | |
| #define xhost_and_af2sockaddr(host, port, af) ((void)(af), xhost2sockaddr((host), (port))) | |
| #endif | |
| - | /* Assign sin[6]_port member if the socket is of corresponding type, |
| + | /* Assign sin[6]_port member if the socket is an AF_INET[6] one, |
| * otherwise no-op. Useful for ftp. | |
| * NB: does NOT do htons() internally, just direct assignment. */ | |
| void set_nport(len_and_sockaddr *lsa, unsigned port); | |