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add comments regarding SO_REUSEADDR

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This commit is contained in:
Denis Vlasenko 2007-08-16 18:27:47 +00:00
parent 06b064c28d
commit 7f175ccbc3
1 changed files with 9 additions and 1 deletions
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10
include/libbb.h
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@ -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);