1 /* NHRP daemon Linux specific glue
2 * Copyright (c) 2014-2015 Timo Teräs
3 *
4 * This file is free software: you may copy, redistribute and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, either version 2 of the License, or
7 * (at your option) any later version.
8 */
9
10 #include <fcntl.h>
11 #include <stdio.h>
12 #include <unistd.h>
13 #include <string.h>
14 #include <sys/ioctl.h>
15 #include <sys/socket.h>
16 #include <sys/types.h>
17 #include <asm/types.h>
18 #include <arpa/inet.h>
19 #include <linux/netlink.h>
20 #include <linux/rtnetlink.h>
21 #include <linux/ip.h>
22 #include <linux/if_arp.h>
23 #include <linux/if_tunnel.h>
24
25 #include "nhrp_protocol.h"
26 #include "os.h"
27 #include "netlink.h"
28
29 static int nhrp_socket_fd = -1;
30
os_socket(void)31 int os_socket(void)
32 {
33 if (nhrp_socket_fd < 0)
34 nhrp_socket_fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_NHRP));
35 return nhrp_socket_fd;
36 }
37
os_sendmsg(const uint8_t * buf,size_t len,int ifindex,const uint8_t * addr,size_t addrlen)38 int os_sendmsg(const uint8_t *buf, size_t len, int ifindex, const uint8_t *addr, size_t addrlen)
39 {
40 struct sockaddr_ll lladdr;
41 struct iovec iov = {
42 .iov_base = (void*) buf,
43 .iov_len = len,
44 };
45 struct msghdr msg = {
46 .msg_name = &lladdr,
47 .msg_namelen = sizeof(lladdr),
48 .msg_iov = &iov,
49 .msg_iovlen = 1,
50 };
51 int status;
52
53 if (addrlen > sizeof(lladdr.sll_addr))
54 return -1;
55
56 memset(&lladdr, 0, sizeof(lladdr));
57 lladdr.sll_family = AF_PACKET;
58 lladdr.sll_protocol = htons(ETH_P_NHRP);
59 lladdr.sll_ifindex = ifindex;
60 lladdr.sll_halen = addrlen;
61 memcpy(lladdr.sll_addr, addr, addrlen);
62
63 status = sendmsg(nhrp_socket_fd, &msg, 0);
64 if (status < 0)
65 return -1;
66
67 return 0;
68 }
69
os_recvmsg(uint8_t * buf,size_t * len,int * ifindex,uint8_t * addr,size_t * addrlen)70 int os_recvmsg(uint8_t *buf, size_t *len, int *ifindex, uint8_t *addr, size_t *addrlen)
71 {
72 struct sockaddr_ll lladdr;
73 struct iovec iov = {
74 .iov_base = buf,
75 .iov_len = *len,
76 };
77 struct msghdr msg = {
78 .msg_name = &lladdr,
79 .msg_namelen = sizeof(lladdr),
80 .msg_iov = &iov,
81 .msg_iovlen = 1,
82 };
83 int r;
84
85 r = recvmsg(nhrp_socket_fd, &msg, MSG_DONTWAIT);
86 if (r < 0)
87 return r;
88
89 *len = r;
90 *ifindex = lladdr.sll_ifindex;
91
92 if (*addrlen <= (size_t) lladdr.sll_addr) {
93 if (memcmp(lladdr.sll_addr, "\x00\x00\x00\x00", 4) != 0) {
94 memcpy(addr, lladdr.sll_addr, lladdr.sll_halen);
95 *addrlen = lladdr.sll_halen;
96 } else {
97 *addrlen = 0;
98 }
99 }
100
101 return 0;
102 }
103
linux_configure_arp(const char * iface,int on)104 static int linux_configure_arp(const char *iface, int on)
105 {
106 struct ifreq ifr;
107
108 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
109 if (ioctl(nhrp_socket_fd, SIOCGIFFLAGS, &ifr))
110 return -1;
111
112 if (on)
113 ifr.ifr_flags &= ~IFF_NOARP;
114 else
115 ifr.ifr_flags |= IFF_NOARP;
116
117 if (ioctl(nhrp_socket_fd, SIOCSIFFLAGS, &ifr))
118 return -1;
119
120 return 0;
121 }
122
linux_icmp_redirect_off(const char * iface)123 static int linux_icmp_redirect_off(const char *iface)
124 {
125 char fname[256];
126 int fd, ret = -1;
127
128 sprintf(fname, "/proc/sys/net/ipv4/conf/%s/send_redirects", iface);
129 fd = open(fname, O_WRONLY);
130 if (fd < 0)
131 return -1;
132 if (write(fd, "0\n", 2) == 2)
133 ret = 0;
134 close(fd);
135
136 return ret;
137 }
138
os_configure_dmvpn(unsigned int ifindex,const char * ifname,int af)139 int os_configure_dmvpn(unsigned int ifindex, const char *ifname, int af)
140 {
141 int ret = 0;
142
143 switch (af) {
144 case AF_INET:
145 ret |= linux_icmp_redirect_off("all");
146 ret |= linux_icmp_redirect_off(ifname);
147 break;
148 }
149 ret |= linux_configure_arp(ifname, 1);
150 ret |= netlink_configure_arp(ifindex, af);
151
152 return ret;
153 }
154