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/*
* LimoX - The Linux on mobile XMPP chat client
* Copyright (C) 2022 xengineering
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdbool.h>
/*
* Get the domainpart of the Jabber ID (JID)
*
* See https://datatracker.ietf.org/doc/html/rfc7622#section-3.2 for details.
*/
char *get_domainpart(char *jid)
{
int start = 0; // inclusive index
int stop = strlen(jid); // exclusive index
for(int i=0; i<strlen(jid); i++) {
if (jid[i] == '/') {
stop = i;
break;
}
}
for(int i=0; i<strlen(jid); i++) {
if (jid[i] == '@') {
start = i + 1;
break;
}
}
char *retval = (char *)malloc((stop-start+1) * sizeof(char));
memcpy(retval, jid+start, (stop-start) * sizeof(char));
retval[stop] = '\0';
return retval;
}
/*
* Return the preferred struct addrinfo * or NULL
*
* This handles DNS resolution. It returns the first valid addrinfo which is
* returned by getaddrinfo. Mind that the addrinfo could use IPv6 instead of
* IPv4.
*
* FIXME this just takes the first received IPv4 address (by far not compliant
* to RFC 6120!)
* FIXME This function contains a memory leak! Free the linked list servinfo!
*/
struct addrinfo *resolve_dns(char *domain)
{
struct addrinfo hints;
struct addrinfo *servinfo;
void *addr;
char ipstr[INET6_ADDRSTRLEN];
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
if (getaddrinfo(domain, "xmpp-client", &hints, &servinfo) != 0) {
printf("Failed to resolve hostname '%s'.\n", domain);
return NULL;
}
struct addrinfo *p;
for(p=servinfo; p!=NULL; p=p->ai_next) {
if (p->ai_family == AF_INET) {
struct sockaddr_in *ipv4 = (struct sockaddr_in *)p->ai_addr;
addr = &(ipv4->sin_addr);
inet_ntop(p->ai_family, addr, ipstr, sizeof ipstr);
printf("Got compatible IPv4 address %s from DNS.\n", ipstr);
return p;
} else if (p->ai_family == AF_INET6) {
printf("Ignored IPv6 DNS entry which is not supported.\n");
} else {
printf("Ignored unknown addrinfo address type.\n");
}
}
printf("No suitable IP address found via DNS!\n");
return NULL;
}
/*
* Start XMPP stream via the given socket filedescriptor
*
* Returns 0 in case of success and -1 otherwise.
*/
int start_stream(int sock_fd, char *jid, char *domainpart)
{
const char *tmpl = "<stream:stream\
from='%s'\
to='%s'\
version='1.0'\
xml:lang='en'\
xmlns='jabber:client'\
xmlns:stream='http://etherx.jabber.org/streams'>";
char *msg;
asprintf(&msg, tmpl, jid, domainpart);
int len = strlen(msg);
int sent = send(sock_fd, msg, len, 0);
if (sent == len) {
printf(">>> %s\n", msg);
return 0;
} else if (sent == 0) {
printf("Failed to send any bytes to server!\n");
return -1;
} else {
printf("Could just send %d bytes of %d bytes to server!\n", sent, len);
return -1;
}
}
/*
* Get JID and password and return true on success
*/
bool get_credentials(char **jid, char **pwd)
{
if (getenv("LIMOX_USER") == NULL || getenv("LIMOX_PWD") == NULL) {
printf("Failed to connect.\n");
printf("Please set the LIMOX_USER and LIMOX_PWD shell variables.\n");
return false;
}
*jid = getenv("LIMOX_USER");
*pwd = getenv("LIMOX_PWD");
return true;
}
/*
* Initialize the network connection to the XMPP server and return socket fd
*
* TODO: Error handling is missing.
*/
int xmpp_connect(void)
{
printf("net_init()\n");
int sock = -1;
char *jid;
char *pwd;
if (!get_credentials(&jid, &pwd)) {
return sock;
}
printf("Trying to connect as '%s' with '%s'.\n", jid, pwd);
char *domain = get_domainpart(jid);
printf("Domainpart is '%s'.\n", domain);
struct addrinfo *addr = resolve_dns(domain);
sock = socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
if (sock == -1) {
printf("Failed to get socket from OS!.");
return sock;
} else {
printf("Got socket number %d from OS.\n", sock);
}
if (connect(sock, addr->ai_addr, addr->ai_addrlen) == -1) {
printf("Failed to connect!\n");
return sock;
} else {
printf("Successfully connected.\n");
}
if (start_stream(sock, jid, domain) == -1) {
printf("Failed to init stream!\n");
return sock;
}
printf("Stream init sent.\n");
return sock;
}
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