1 /*
2 * dhcpcd - DHCP client daemon
3 * Copyright (c) 2006-2011 Roy Marples <roy@marples.name>
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/types.h>
28 #include <sys/ioctl.h>
29 #include <sys/socket.h>
30
31 #include <net/if.h>
32 #include <netinet/in_systm.h>
33 #include <netinet/in.h>
34 #include <arpa/inet.h>
35
36 #ifdef __linux__
37 # include <asm/types.h> /* needed for 2.4 kernels for the below header */
38 # include <linux/filter.h>
39 # include <linux/if_packet.h>
40 # define bpf_insn sock_filter
41 # define BPF_SKIPTYPE
42 # define BPF_ETHCOOK -ETH_HLEN
43 # define BPF_WHOLEPACKET 0x0fffffff /* work around buggy LPF filters */
44 #endif
45
46 #include <errno.h>
47 #include <fcntl.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <time.h>
52 #include <unistd.h>
53
54 #include "config.h"
55 #include "common.h"
56 #include "dhcp.h"
57 #include "net.h"
58 #include "bpf-filter.h"
59
60 /* Broadcast address for IPoIB */
61 static const uint8_t ipv4_bcast_addr[] = {
62 0x00, 0xff, 0xff, 0xff,
63 0xff, 0x12, 0x40, 0x1b, 0x00, 0x00, 0x00, 0x00,
64 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff
65 };
66
67 int
open_socket(struct interface * iface,int protocol)68 open_socket(struct interface *iface, int protocol)
69 {
70 int s;
71 union sockunion {
72 struct sockaddr sa;
73 struct sockaddr_in sin;
74 struct sockaddr_ll sll;
75 struct sockaddr_storage ss;
76 } su;
77 struct sock_fprog pf;
78 int *fd;
79 #ifdef PACKET_AUXDATA
80 int n;
81 #endif
82
83 if ((s = socket(PF_PACKET, SOCK_DGRAM, htons(protocol))) == -1)
84 return -1;
85
86 memset(&su, 0, sizeof(su));
87 su.sll.sll_family = PF_PACKET;
88 su.sll.sll_protocol = htons(protocol);
89 if (!(su.sll.sll_ifindex = if_nametoindex(iface->name))) {
90 errno = ENOENT;
91 goto eexit;
92 }
93 /* Install the DHCP filter */
94 memset(&pf, 0, sizeof(pf));
95 if (protocol == ETHERTYPE_ARP) {
96 pf.filter = UNCONST(arp_bpf_filter);
97 pf.len = arp_bpf_filter_len;
98 } else {
99 pf.filter = UNCONST(dhcp_bpf_filter);
100 pf.len = dhcp_bpf_filter_len;
101 }
102 if (setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &pf, sizeof(pf)) != 0)
103 goto eexit;
104 #ifdef PACKET_AUXDATA
105 n = 1;
106 if (setsockopt(s, SOL_PACKET, PACKET_AUXDATA, &n, sizeof(n)) != 0) {
107 if (errno != ENOPROTOOPT)
108 goto eexit;
109 }
110 #endif
111 if (set_cloexec(s) == -1)
112 goto eexit;
113 if (set_nonblock(s) == -1)
114 goto eexit;
115 if (bind(s, &su.sa, sizeof(su)) == -1)
116 goto eexit;
117 if (protocol == ETHERTYPE_ARP)
118 fd = &iface->arp_fd;
119 else
120 fd = &iface->raw_fd;
121 if (*fd != -1)
122 close(*fd);
123 *fd = s;
124 return s;
125
126 eexit:
127 close(s);
128 return -1;
129 }
130
131 ssize_t
send_raw_packet(const struct interface * iface,int protocol,const void * data,ssize_t len)132 send_raw_packet(const struct interface *iface, int protocol,
133 const void *data, ssize_t len)
134 {
135 union sockunion {
136 struct sockaddr sa;
137 struct sockaddr_ll sll;
138 struct sockaddr_storage ss;
139 } su;
140 int fd;
141
142 memset(&su, 0, sizeof(su));
143 su.sll.sll_family = AF_PACKET;
144 su.sll.sll_protocol = htons(protocol);
145 if (!(su.sll.sll_ifindex = if_nametoindex(iface->name))) {
146 errno = ENOENT;
147 return -1;
148 }
149 su.sll.sll_hatype = htons(iface->family);
150 su.sll.sll_halen = iface->hwlen;
151 if (iface->family == ARPHRD_INFINIBAND)
152 memcpy(&su.sll.sll_addr,
153 &ipv4_bcast_addr, sizeof(ipv4_bcast_addr));
154 else
155 memset(&su.sll.sll_addr, 0xff, iface->hwlen);
156 if (protocol == ETHERTYPE_ARP)
157 fd = iface->arp_fd;
158 else
159 fd = iface->raw_fd;
160
161 return sendto(fd, data, len, 0, &su.sa, sizeof(su));
162 }
163
164 ssize_t
get_raw_packet(struct interface * iface,int protocol,void * data,ssize_t len,int * partialcsum)165 get_raw_packet(struct interface *iface, int protocol,
166 void *data, ssize_t len, int *partialcsum)
167 {
168 struct iovec iov = {
169 .iov_base = data,
170 .iov_len = len,
171 };
172 struct msghdr msg = {
173 .msg_iov = &iov,
174 .msg_iovlen = 1,
175 };
176 #ifdef PACKET_AUXDATA
177 unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
178 struct cmsghdr *cmsg;
179 struct tpacket_auxdata *aux;
180 #endif
181
182 ssize_t bytes;
183 int fd = -1;
184
185 #ifdef PACKET_AUXDATA
186 msg.msg_control = cmsgbuf;
187 msg.msg_controllen = sizeof(cmsgbuf);
188 #endif
189
190 if (protocol == ETHERTYPE_ARP)
191 fd = iface->arp_fd;
192 else
193 fd = iface->raw_fd;
194 bytes = recvmsg(fd, &msg, 0);
195 if (bytes == -1)
196 return errno == EAGAIN ? 0 : -1;
197 if (partialcsum != NULL) {
198 *partialcsum = 0;
199 #ifdef PACKET_AUXDATA
200 for (cmsg = CMSG_FIRSTHDR(&msg);
201 cmsg;
202 cmsg = CMSG_NXTHDR(&msg, cmsg))
203 {
204 if (cmsg->cmsg_level == SOL_PACKET &&
205 cmsg->cmsg_type == PACKET_AUXDATA) {
206 aux = (void *)CMSG_DATA(cmsg);
207 *partialcsum = aux->tp_status &
208 TP_STATUS_CSUMNOTREADY;
209 }
210 }
211 #endif
212 }
213 return bytes;
214 }
215