1 // vim: noet sw=4 ts=4:
3 ==================================================================================
4 Copyright (c) 2020 Nokia
5 Copyright (c) 2020 AT&T Intellectual Property.
7 Licensed under the Apache License, Version 2.0 (the "License");
8 you may not use this file except in compliance with the License.
9 You may obtain a copy of the License at
11 http://www.apache.org/licenses/LICENSE-2.0
13 Unless required by applicable law or agreed to in writing, software
14 distributed under the License is distributed on an "AS IS" BASIS,
15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 See the License for the specific language governing permissions and
17 limitations under the License.
18 ==================================================================================
23 *-----------------------------------------------------------------------------------
25 * Mnemonic: SIestablish
26 * Abstract:i Prep functions that set up a socket for listening or making a
29 * Author: E. Scott Daniels
31 * Modified: 19 Apr 1995 - To keep returned address of the port.
32 * 08 Mar 2007 - conversion for ipv6.
33 * 12 Oct 2020 - split into connect prep and listen prep
35 *-----------------------------------------------------------------------------------
39 #include "sisetup.h" // include the necessary setup stuff
40 #include "sitransport.h"
42 #include <netinet/tcp.h>
45 #define SO_REUSEPORT 0
49 Prep a socket for "listening."
50 This routine will open a socket and bind an address to it in
51 preparation for listening for connections or inbound UDP
52 datagrams. A file descriptor for the socket is captured and all
53 related information is placed into a transport provider (tp) block.
55 Type is the SI constant UDP_DEVICE or TCP_DEVICE
56 abuf points to the address that is to be bound to the socket.
57 Family is one of the AF_* constants (AF_ANY, AF_INET or AF_INET6)
59 The address should be one of these forms:
60 [::1]:port v6 localhost device (loop back)
61 localhost:port v4 or 6 loopback depending on /etc/hosts
62 0.0.0.0:port any interface
63 addr:port an address assigned to one of the devices
65 Returns a transport struct which is the main context for the listener.
67 extern struct tp_blk *SIlisten_prep( int type, char* abuf, int family ) {
68 struct tp_blk *tptr; // pointer at new tp block
69 int status = SI_OK; // processing status
70 struct sockaddr *addr; // IP address we are requesting
71 int protocol; // protocol for socket call
75 tptr = (struct tp_blk *) SInew( TP_BLK ); // new transport info block
81 switch( type ) // things specifc to tcp or udp
84 tptr->type = SOCK_DGRAM;
85 protocol = IPPROTO_UDP;
90 tptr->type = SOCK_STREAM;
91 protocol = IPPROTO_TCP;
94 alen = SIgenaddr( abuf, protocol, family, tptr->type, &addr ); // family == 0 for type that suits the address passed in
97 free( addr ); // not needed, but scanners complain if we don't overtly do this
102 tptr->family = addr->sa_family;
104 if( (tptr->fd = SOCKET( tptr->family, tptr->type, protocol )) >= SI_OK ) {
107 SETSOCKOPT(tptr->fd, SOL_SOCKET, SO_REUSEPORT, (char *)&optval, sizeof( optval) ) ;
110 status = BIND( tptr->fd, (struct sockaddr *) addr, alen );
111 if( status == SI_OK ) {
112 tptr->addr = addr; // save address
114 fprintf( stderr, "<ERR> siestablish: bind failed: fam=%d type=%d pro=%d %s\n", tptr->family, tptr->type, protocol, strerror( errno ) );
118 status = ! SI_OK; // force bad return later
119 fprintf( stderr, "<ERR> siestablish: socket not esablished: fam=%d type=%d pro=%d %s\n", tptr->family, tptr->type, protocol, strerror( errno ) );
122 if( status != SI_OK ) { // socket or bind call failed - clean up stuff
123 fprintf( stderr, "<ERR> siestablish: bad state -- returning nil pointer\n" );
125 SItrash( TP_BLK, tptr ); // free the trasnsport block
126 tptr = NULL; // set to return nothing
134 Look at the address and determine if the connect attempt to this address must
135 use safe_connect() rather than the system connect() call. On linux, a smart
136 connect is needed if the target port is >32K and is even. This makes the assumption
137 that the local port rage floor is 32K; we could read something in /proc, but
138 at this point won't bother. Returns true if we determine that it is best to
141 static int need_smartc( char* abuf ) {
146 if( (tok = strchr( abuf, ':')) != NULL ) {
148 if( v < 32767 || v % 2 != 0 ) {
157 Prep a socket to use to connect to a listener.
158 Establish a transport block and target address in prep to connect.
159 Type is the SI constant UDP_DEVICE or TCP_DEVICE. The abuf pointer
160 should point to either a name:port or IP:port string. Family should
161 be 0 to select the family best suited to the address provided, or
162 any (v4 or v6) if the address is a name. If a perticular type is
163 desired family should be either AF_INET or AF_INET6. Using a
164 family of 0 (AF_ANY) is usually the best choice.
166 extern struct tp_blk *SIconn_prep( struct ginfo_blk *gptr, int type, char *abuf, int family ) {
167 struct tp_blk *tptr; // pointer at new tp block
168 struct sockaddr *addr; // IP address we are requesting
169 int protocol; // protocol for socket call
170 char buf[256]; // buffer to build request address in
174 tptr = (struct tp_blk *) SInew( TP_BLK ); // new transport info block
180 switch( type ) // things specifc to tcp or udp
183 tptr->type = SOCK_DGRAM;
184 protocol = IPPROTO_UDP;
189 tptr->type = SOCK_STREAM;
190 protocol = IPPROTO_TCP;
193 alen = SIgenaddr( abuf, protocol, family, tptr->type, &addr ); // family == 0 for type that suits the address passed in
195 if( addr != NULL ) { // not needed, but scanners complain if we don't overtly do this
201 tptr->family = addr->sa_family;
204 if( (tptr->fd = SOCKET( tptr->family, tptr->type, protocol )) >= SI_OK ) {
207 if( gptr->tcp_flags & SI_TF_NODELAY ) {
212 SETSOCKOPT( tptr->fd, SOL_TCP, TCP_NODELAY, (void *)&optval, sizeof( optval) ) ;
214 if( gptr->tcp_flags & SI_TF_FASTACK ) {
219 SETSOCKOPT( tptr->fd, SOL_TCP, TCP_QUICKACK, (void *)&optval, sizeof( optval) ) ;
221 tptr->paddr = addr; // tuck the remote peer address away
222 if( need_smartc( abuf ) ) {
223 tptr->flags |= TPF_SAFEC;
227 SItrash( TP_BLK, tptr ); // free the trasnsport block
228 tptr = NULL; // we'll return nil