1
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <unistd.h>
5
6 #include <errno.h>
7 #include <string.h>
8 #include <ctype.h>
9
10 #include <sys/socket.h>
11 #include <netinet/in.h>
12 #include <linux/if.h>
13 #include <linux/sockios.h>
14 #include <arpa/inet.h>
15
die(const char * s)16 static void die(const char *s)
17 {
18 fprintf(stderr,"error: %s (%s)\n", s, strerror(errno));
19 exit(-1);
20 }
21
setflags(int s,struct ifreq * ifr,int set,int clr)22 static void setflags(int s, struct ifreq *ifr, int set, int clr)
23 {
24 if(ioctl(s, SIOCGIFFLAGS, ifr) < 0) die("SIOCGIFFLAGS");
25 ifr->ifr_flags = (ifr->ifr_flags & (~clr)) | set;
26 if(ioctl(s, SIOCSIFFLAGS, ifr) < 0) die("SIOCSIFFLAGS");
27 }
28
init_sockaddr_in(struct sockaddr_in * sin,const char * addr)29 static inline void init_sockaddr_in(struct sockaddr_in *sin, const char *addr)
30 {
31 sin->sin_family = AF_INET;
32 sin->sin_port = 0;
33 sin->sin_addr.s_addr = inet_addr(addr);
34 }
35
setmtu(int s,struct ifreq * ifr,const char * mtu)36 static void setmtu(int s, struct ifreq *ifr, const char *mtu)
37 {
38 int m = atoi(mtu);
39 ifr->ifr_mtu = m;
40 if(ioctl(s, SIOCSIFMTU, ifr) < 0) die("SIOCSIFMTU");
41 }
setdstaddr(int s,struct ifreq * ifr,const char * addr)42 static void setdstaddr(int s, struct ifreq *ifr, const char *addr)
43 {
44 init_sockaddr_in((struct sockaddr_in *) &ifr->ifr_dstaddr, addr);
45 if(ioctl(s, SIOCSIFDSTADDR, ifr) < 0) die("SIOCSIFDSTADDR");
46 }
47
setnetmask(int s,struct ifreq * ifr,const char * addr)48 static void setnetmask(int s, struct ifreq *ifr, const char *addr)
49 {
50 init_sockaddr_in((struct sockaddr_in *) &ifr->ifr_netmask, addr);
51 if(ioctl(s, SIOCSIFNETMASK, ifr) < 0) die("SIOCSIFNETMASK");
52 }
53
setaddr(int s,struct ifreq * ifr,const char * addr)54 static void setaddr(int s, struct ifreq *ifr, const char *addr)
55 {
56 init_sockaddr_in((struct sockaddr_in *) &ifr->ifr_addr, addr);
57 if(ioctl(s, SIOCSIFADDR, ifr) < 0) die("SIOCSIFADDR");
58 }
59
ifconfig_main(int argc,char * argv[])60 int ifconfig_main(int argc, char *argv[])
61 {
62 struct ifreq ifr;
63 int s;
64 unsigned int addr, mask, flags;
65 char astring[20];
66 char mstring[20];
67 char *updown, *brdcst, *loopbk, *ppp, *running, *multi;
68
69 argc--;
70 argv++;
71
72 if(argc == 0) return 0;
73
74 memset(&ifr, 0, sizeof(struct ifreq));
75 strncpy(ifr.ifr_name, argv[0], IFNAMSIZ);
76 ifr.ifr_name[IFNAMSIZ-1] = 0;
77 argc--, argv++;
78
79 if((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
80 die("cannot open control socket\n");
81 }
82
83 if (argc == 0) {
84 if (ioctl(s, SIOCGIFADDR, &ifr) < 0) {
85 perror(ifr.ifr_name);
86 return -1;
87 } else
88 addr = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr;
89
90 if (ioctl(s, SIOCGIFNETMASK, &ifr) < 0) {
91 perror(ifr.ifr_name);
92 return -1;
93 } else
94 mask = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr;
95
96 if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0) {
97 perror(ifr.ifr_name);
98 return -1;
99 } else
100 flags = ifr.ifr_flags;
101
102 sprintf(astring, "%d.%d.%d.%d",
103 addr & 0xff,
104 ((addr >> 8) & 0xff),
105 ((addr >> 16) & 0xff),
106 ((addr >> 24) & 0xff));
107 sprintf(mstring, "%d.%d.%d.%d",
108 mask & 0xff,
109 ((mask >> 8) & 0xff),
110 ((mask >> 16) & 0xff),
111 ((mask >> 24) & 0xff));
112 printf("%s: ip %s mask %s flags [", ifr.ifr_name,
113 astring,
114 mstring
115 );
116
117 updown = (flags & IFF_UP) ? "up" : "down";
118 brdcst = (flags & IFF_BROADCAST) ? " broadcast" : "";
119 loopbk = (flags & IFF_LOOPBACK) ? " loopback" : "";
120 ppp = (flags & IFF_POINTOPOINT) ? " point-to-point" : "";
121 running = (flags & IFF_RUNNING) ? " running" : "";
122 multi = (flags & IFF_MULTICAST) ? " multicast" : "";
123 printf("%s%s%s%s%s%s]\n", updown, brdcst, loopbk, ppp, running, multi);
124 return 0;
125 }
126
127 while(argc > 0) {
128 if (!strcmp(argv[0], "up")) {
129 setflags(s, &ifr, IFF_UP, 0);
130 } else if (!strcmp(argv[0], "mtu")) {
131 argc--, argv++;
132 if (!argc) {
133 errno = EINVAL;
134 die("expecting a value for parameter \"mtu\"");
135 }
136 setmtu(s, &ifr, argv[0]);
137 } else if (!strcmp(argv[0], "-pointopoint")) {
138 setflags(s, &ifr, IFF_POINTOPOINT, 1);
139 } else if (!strcmp(argv[0], "pointopoint")) {
140 argc--, argv++;
141 if (!argc) {
142 errno = EINVAL;
143 die("expecting an IP address for parameter \"pointtopoint\"");
144 }
145 setdstaddr(s, &ifr, argv[0]);
146 setflags(s, &ifr, IFF_POINTOPOINT, 0);
147 } else if (!strcmp(argv[0], "down")) {
148 setflags(s, &ifr, 0, IFF_UP);
149 } else if (!strcmp(argv[0], "netmask")) {
150 argc--, argv++;
151 if (!argc) {
152 errno = EINVAL;
153 die("expecting an IP address for parameter \"netmask\"");
154 }
155 setnetmask(s, &ifr, argv[0]);
156 } else if (isdigit(argv[0][0])) {
157 setaddr(s, &ifr, argv[0]);
158 setflags(s, &ifr, IFF_UP, 0);
159 }
160 argc--, argv++;
161 }
162 return 0;
163 }
164