ifconfig.c revision 4f6e8d7a00cbeda1e70cc15be9c4af1018bdad53 
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
16static void die(const char *s)
17{
18    fprintf(stderr,"error: %s (%s)\n", s, strerror(errno));
19    exit(-1);
20}
21
22static 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
29static 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
36static void setnetmask(int s, struct ifreq *ifr, const char *addr)
37{
38	init_sockaddr_in((struct sockaddr_in *) &ifr->ifr_netmask, addr);
39    if(ioctl(s, SIOCSIFNETMASK, ifr) < 0) die("SIOCSIFNETMASK");
40}
41
42static void setaddr(int s, struct ifreq *ifr, const char *addr)
43{
44	init_sockaddr_in((struct sockaddr_in *) &ifr->ifr_addr, addr);
45    if(ioctl(s, SIOCSIFADDR, ifr) < 0) die("SIOCSIFADDR");
46}
47
48int ifconfig_main(int argc, char *argv[])
49{
50    struct ifreq ifr;
51    int s;
52    unsigned int addr, mask, flags;
53    char astring[20];
54    char mstring[20];
55    char *updown, *brdcst, *loopbk, *ppp, *running, *multi;
56
57    argc--;
58    argv++;
59
60    if(argc == 0) return 0;
61
62    memset(&ifr, 0, sizeof(struct ifreq));
63    strncpy(ifr.ifr_name, argv[0], IFNAMSIZ);
64    ifr.ifr_name[IFNAMSIZ-1] = 0;
65    argc--, argv++;
66
67    if((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
68        die("cannot open control socket\n");
69    }
70
71    if (argc == 0) {
72        if (ioctl(s, SIOCGIFADDR, &ifr) < 0) {
73            perror(ifr.ifr_name);
74            return -1;
75        } else
76            addr = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr;
77
78        if (ioctl(s, SIOCGIFNETMASK, &ifr) < 0) {
79            perror(ifr.ifr_name);
80            return -1;
81        } else
82            mask = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr;
83
84        if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0) {
85            perror(ifr.ifr_name);
86            return -1;
87        } else
88            flags = ifr.ifr_flags;
89
90        sprintf(astring, "%d.%d.%d.%d",
91                addr & 0xff,
92                ((addr >> 8) & 0xff),
93                ((addr >> 16) & 0xff),
94                ((addr >> 24) & 0xff));
95        sprintf(mstring, "%d.%d.%d.%d",
96                mask & 0xff,
97                ((mask >> 8) & 0xff),
98                ((mask >> 16) & 0xff),
99                ((mask >> 24) & 0xff));
100        printf("%s: ip %s mask %s flags [", ifr.ifr_name,
101               astring,
102               mstring
103               );
104
105        updown =  (flags & IFF_UP)           ? "up" : "down";
106        brdcst =  (flags & IFF_BROADCAST)    ? " broadcast" : "";
107        loopbk =  (flags & IFF_LOOPBACK)     ? " loopback" : "";
108        ppp =     (flags & IFF_POINTOPOINT)  ? " point-to-point" : "";
109        running = (flags & IFF_RUNNING)      ? " running" : "";
110        multi =   (flags & IFF_MULTICAST)    ? " multicast" : "";
111        printf("%s%s%s%s%s%s]\n", updown, brdcst, loopbk, ppp, running, multi);
112
113
114
115/*    char *updown, *brdcst, *loopbk, *ppp, *running, *multi; */
116
117        return 0;
118    }
119
120    while(argc > 0){
121        if(!strcmp(argv[0], "up")) {
122            setflags(s, &ifr, IFF_UP, 0);
123        } else if(!strcmp(argv[0], "down")) {
124            setflags(s, &ifr, 0, IFF_UP);
125		} else if(!strcmp(argv[0], "netmask")) {
126			argc--, argv++;
127			if (0 == argc) {
128				errno = EINVAL;
129				die("expecting an IP address for parameter \"netmask\"");
130			}
131			setnetmask(s, &ifr, argv[0]);
132        } else if(isdigit(argv[0][0])){
133            setaddr(s, &ifr, argv[0]);
134        }
135        argc--, argv++;
136    }
137
138    return 0;
139}
140