1/* vi: set sw=4 ts=4: */
2/*
3 * DHCP server client/server socket creation
4 *
5 * udhcp client/server
6 * Copyright (C) 1999 Matthew Ramsay <matthewr@moreton.com.au>
7 *			Chris Trew <ctrew@moreton.com.au>
8 *
9 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 */
25#include "common.h"
26#include <net/if.h>
27
28int FAST_FUNC udhcp_read_interface(const char *interface, int *ifindex,
29		uint32_t *nip, uint8_t *mac, uint16_t *mtu)
30{
31	/* char buffer instead of bona-fide struct avoids aliasing warning */
32	char ifr_buf[sizeof(struct ifreq)];
33	struct ifreq *const ifr = (void *)ifr_buf;
34
35	int fd;
36	struct sockaddr_in *our_ip;
37
38	memset(ifr, 0, sizeof(*ifr));
39	fd = xsocket(AF_INET, SOCK_RAW, IPPROTO_RAW);
40
41	ifr->ifr_addr.sa_family = AF_INET;
42	strncpy_IFNAMSIZ(ifr->ifr_name, interface);
43	if (nip) {
44		if (ioctl_or_perror(fd, SIOCGIFADDR, ifr,
45			"is interface %s up and configured?", interface)
46		) {
47			close(fd);
48			return -1;
49		}
50		our_ip = (struct sockaddr_in *) &ifr->ifr_addr;
51		*nip = our_ip->sin_addr.s_addr;
52		log1("IP %s", inet_ntoa(our_ip->sin_addr));
53	}
54
55	if (ifindex) {
56		if (ioctl_or_warn(fd, SIOCGIFINDEX, ifr) != 0) {
57			close(fd);
58			return -1;
59		}
60		log1("Adapter index %d", ifr->ifr_ifindex);
61		*ifindex = ifr->ifr_ifindex;
62	}
63
64	if (mac) {
65		if (ioctl_or_warn(fd, SIOCGIFHWADDR, ifr) != 0) {
66			close(fd);
67			return -1;
68		}
69		memcpy(mac, ifr->ifr_hwaddr.sa_data, 6);
70		log1("MAC %02x:%02x:%02x:%02x:%02x:%02x",
71			mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
72	}
73
74	if (mtu) {
75		if (ioctl_or_warn(fd, SIOCGIFMTU, ifr) != 0) {
76			close(fd);
77			return -1;
78		}
79		log1("Adapter mtu %d", ifr->ifr_mtu);
80		*mtu = ifr->ifr_mtu;
81	}
82
83	close(fd);
84	return 0;
85}
86
87/* 1. None of the callers expects it to ever fail */
88/* 2. ip was always INADDR_ANY */
89int FAST_FUNC udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf)
90{
91	int fd;
92	struct sockaddr_in addr;
93	char *colon;
94
95	log1("Opening listen socket on *:%d %s", port, inf);
96	fd = xsocket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
97
98	setsockopt_reuseaddr(fd);
99	if (setsockopt_broadcast(fd) == -1)
100		bb_perror_msg_and_die("SO_BROADCAST");
101
102	/* SO_BINDTODEVICE doesn't work on ethernet aliases (ethN:M) */
103	colon = strrchr(inf, ':');
104	if (colon)
105		*colon = '\0';
106
107	if (setsockopt_bindtodevice(fd, inf))
108		xfunc_die(); /* warning is already printed */
109
110	if (colon)
111		*colon = ':';
112
113	memset(&addr, 0, sizeof(addr));
114	addr.sin_family = AF_INET;
115	addr.sin_port = htons(port);
116	/* addr.sin_addr.s_addr = ip; - all-zeros is INADDR_ANY */
117	xbind(fd, (struct sockaddr *)&addr, sizeof(addr));
118
119	return fd;
120}
121