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[tcpip] Allow binding to unspecified privileged ports (below 1024)

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Originally-implemented-by: Marin Hannache <git@mareo.fr>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2013-08-06 15:56:54 +01:00
parent 0350682865
commit 252d28f098
5 changed files with 117 additions and 81 deletions
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44
src/net/tcpip.c
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@@ -1,4 +1,5 @@
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <byteswap.h>
@@ -133,3 +134,46 @@ uint16_t generic_tcpip_continue_chksum ( uint16_t partial,
uint16_t tcpip_chksum ( const void *data, size_t len ) {
return tcpip_continue_chksum ( TCPIP_EMPTY_CSUM, data, len );
}
/**
* Bind to local TCP/IP port
*
* @v st_local Local TCP/IP socket address, or NULL
* @v available Function to check port availability
* @ret port Local port number, or negative error
*/
int tcpip_bind ( struct sockaddr_tcpip *st_local,
int ( * available ) ( int port ) ) {
uint16_t flags = 0;
uint16_t try_port = 0;
uint16_t min_port;
uint16_t max_port;
unsigned int offset;
unsigned int i;
/* Extract parameters from local socket address */
if ( st_local ) {
flags = st_local->st_flags;
try_port = ntohs ( st_local->st_port );
}
/* If an explicit port is specified, check its availability */
if ( try_port )
return available ( try_port );
/* Otherwise, find an available port in the range [1,1023] or
* [1025,65535] as appropriate.
*/
min_port = ( ( ( ! flags ) & TCPIP_BIND_PRIVILEGED ) + 1 );
max_port = ( ( flags & TCPIP_BIND_PRIVILEGED ) - 1 );
offset = random();
for ( i = 0 ; i <= max_port ; i++ ) {
try_port = ( ( i + offset ) & max_port );
if ( try_port < min_port )
continue;
if ( available ( try_port ) < 0 )
continue;
return try_port;
}
return -EADDRINUSE;
}