summaryrefslogtreecommitdiff
path: root/xmpp.c
blob: 240dfc155a2d90fc329f202daf7f0a75b068e2f3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
/*
 *  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/>.
 */


#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.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
	int stop = strlen(jid);  // exclusive

	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 *get_addrinfo(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;
}

/*
 * Initialize the network connection to the XMPP server
 *
 * TODO: Error handling is missing.
 */
void xmpp_connect(void)
{
	printf("net_init()\n");

	char *jid = getenv("LIMOX_USER");
	char *pwd = getenv("LIMOX_PWD");
	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 = get_addrinfo(domain);

	int sock = socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
	if (sock == -1) {
		printf("Failed to get socket from OS!.");
		return;
	} 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;
	} else {
		printf("Successfully connected.\n");
	}
}