***************************************************************************
*
* Mnemonic: SIconnect
-* Abstract: Start a TCP/IP session with another process.
-* Parms:
-* addr - Pointer to a string containing the process' address
-* The address is either ipv4 or ipv6 formmat with the
-* port number separated with a semicolon (::1;4444,
-* localhost;4444 climber;4444 129.168.0.4;4444).
-* Returns: The session number if all goes well, SI_ERROR if not.
+* Abstract: This module contains functions to make the connection using
+* a transport block which has been given a transport (tcp) family
+* address structure.
*
* Date: March 1995
* Author: E. Scott Daniels
*
-* Mod: 08 Mar 2007 - conversion of sorts to support ipv6
+* Mod: 08 Mar 2007 - conversion of sorts to support ipv6
+* 17 Apr 2020 - Add safe connect capabilities
******************************************************************************
*/
#include "sisetup.h"
#include "sitransport.h"
+// ---------------- internal functions ----------------------------------------------
+
+/*
+ Attempts a connection to addr, and ensures that the linux even port
+ connect bug does not establish the connection back to our process.
+ If we detect this, then we abort the connection and return -1. 0
+ returned on a good connection.
+
+ If we are hit with the even port connection bug we have no choice but
+ to abort the connection which will CLOSE the caller's FD. This may
+ not be expected in some situations, and when we do the errno is set to
+ EBADFD to indicate this. We ensure that this state is returned ONLY
+ if the failure results in a closed fd which the caller will need to reopen.
+*/
+int safe_connect( int fd, struct sockaddr* addr, int alen ) {
+ int state = 0;
+ char caddr[255]; // work buffer for get sock name (v6 addr ~28 bytes, so this is plenty)
+ int calen; // len of the connect generated address
+
+ if( (state = CONNECT( fd, addr, alen )) != 0 ) {
+ if( errno == EBADFD ) { // ensure we return bad fd ONLY if we abort later
+ errno = ECONNABORTED;
+ }
+ return state;
+ }
+
+ if( PARANOID_CHECKS ) {
+ if( alen > sizeof( caddr ) ) { // shouldn't happen, but be safe
+ fprintf( stderr, "safe_connect: address buffer for connect exceeds work space %d > %lu\n", alen, sizeof( caddr ) );
+ errno = E2BIG;
+ return -1;
+ }
+ }
+
+ calen = alen; // we assume a bound address will have the same type, and thus len, as the connect to addr
+ if( getsockname( fd, (struct sockaddr *) &caddr, &calen ) == 0 ) {
+ if( calen != alen || memcmp( addr, &caddr, calen ) != 0 ) { // addresses differ, so it's good
+ errno = 0;
+ return 0;
+ }
+ }
+
+ siabort_conn( fd );
+ errno = EBADFD;
+ return -1;
+}
+
/*
Accept a file descriptor and add it to the map.
*/
}
}
+/*
+ Creates a connection to the target endpoint using the address in the
+ buffer provided. The address may be one of three forms:
+ hostname:port
+ IPv4-address:port
+ [IPv6-address]:port
+
+ On success the open file descriptor is returned; else -1 is returned. Errno
+ will be left set by the underlying connect() call.
+
+ To avoid the even port connect bug in the linux connect() systeem call,
+ we will use safe_connect() if indicated during the connection prep
+ process.
+*/
extern int SIconnect( struct ginfo_blk *gptr, char *abuf ) {
int status;
- struct tp_blk *tpptr; // pointer to new block
+ struct tp_blk *tpptr; // pointer to new block
struct sockaddr *taddr; // convenience pointer to addr of target
- int alen = 0; // len of address struct
- int fd = SI_ERROR; // file descriptor to return to caller
+ int alen = 0; // len of address struct
+ int fd = SI_ERROR; // file descriptor to return to caller
if( PARANOID_CHECKS ) {
if( gptr == NULL ) {
if( tpptr != NULL ) {
taddr = tpptr->paddr;
errno = 0;
- if( connect( tpptr->fd, taddr, tpptr->palen ) != 0 ) {
- close( tpptr->fd ); // clean up fd and tp_block
- SItrash( TP_BLK, tpptr ); // free the trasnsport block
- fd = SI_ERROR; // send bad session id num back
- } else { // connect ok
- tpptr->flags |= TPF_SESSION; // indicate we have a session here
- tpptr->next = gptr->tplist; // add block to the list
+ if( tpptr->flags & TPF_SAFEC ) {
+ if( safe_connect( tpptr->fd, taddr, tpptr->palen ) != 0 ) { // fd closed on failure
+ SItrash( TP_BLK, tpptr );
+ tpptr->fd = -1;
+ }
+ } else {
+ if( CONNECT( tpptr->fd, taddr, tpptr->palen ) != 0 ) {
+ CLOSE( tpptr->fd ); // clean up fd and tp_block
+ tpptr->fd = -1;
+ SItrash( TP_BLK, tpptr ); // free the trasnsport block
+ }
+ }
+
+ if( tpptr->fd >= 0 ) { // connect ok
+ tpptr->flags |= TPF_SESSION; // indicate we have a session here
+ tpptr->next = gptr->tplist; // add block to the list
if( tpptr->next != NULL ) {
- tpptr->next->prev = tpptr; // if there - point back at new
+ tpptr->next->prev = tpptr; // if there - point back at new
}
- gptr->tplist = tpptr; // point at new head
- fd = tpptr->fd; // save for return value
+ gptr->tplist = tpptr; // point at new head
+ fd = tpptr->fd; // save for return value
SImap_fd( gptr, fd, tpptr );
}
}
- return fd;
-}
+ return fd;
+}
Code Review / ric-plt / lib / rmr.git / blobdiff