route.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#include <linux/route.h>
16
17static void die(const char *s)
18{
19    fprintf(stderr,"error: %s (%s)\n", s, strerror(errno));
20    exit(-1);
21}
22
23static inline void init_sockaddr_in(struct sockaddr_in *sin, const char *addr)
24{
25	sin->sin_family = AF_INET;
26	sin->sin_port = 0;
27	sin->sin_addr.s_addr = inet_addr(addr);
28}
29
30#define ADVANCE(argc, argv) do { argc--, argv++; } while(0)
31#define EXPECT_NEXT(argc, argv) do {        \
32    ADVANCE(argc, argv);                    \
33	if (0 == argc) {  						\
34		errno = EINVAL;                     \
35		die("expecting one more argument"); \
36	}                                       \
37} while(0)
38
39/* current support two kinds of usage */
40/* route add default dev wlan0 */
41/* route add default gw 192.168.20.1 dev wlan0 */
42
43int route_main(int argc, char *argv[])
44{
45    struct ifreq ifr;
46    int s,i;
47	struct rtentry rt;
48	struct sockaddr_in ina;
49
50    if(argc == 0) return 0;
51
52    strncpy(ifr.ifr_name, argv[0], IFNAMSIZ);
53    ifr.ifr_name[IFNAMSIZ-1] = 0;
54	ADVANCE(argc, argv);
55
56    if((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
57        die("cannot open control socket\n");
58    }
59
60    while(argc > 0){
61        if(!strcmp(argv[0], "add")) {
62			EXPECT_NEXT(argc, argv);
63			if(!strcmp(argv[0], "default")) {
64				EXPECT_NEXT(argc, argv);
65				memset((char *) &rt, 0, sizeof(struct rtentry));
66				rt.rt_dst.sa_family = AF_INET;
67				if(!strcmp(argv[0], "dev")) {
68				  EXPECT_NEXT(argc, argv);
69				  rt.rt_flags = RTF_UP | RTF_HOST;
70				  rt.rt_dev = argv[0];
71				  if (ioctl(s, SIOCADDRT, &rt) < 0) die("SIOCADDRT");
72				}else if(!strcmp(argv[0], "gw")) {
73				  EXPECT_NEXT(argc, argv);
74				  rt.rt_flags = RTF_UP | RTF_GATEWAY;
75				  init_sockaddr_in((struct sockaddr_in *)&(rt.rt_genmask), "0.0.0.0");
76				  if(isdigit(argv[0][0])){
77					init_sockaddr_in((struct sockaddr_in *)&(rt.rt_gateway), argv[0]);
78				  }else{
79					die("expecting an IP address for parameter \"gw\"");
80				  }
81				  EXPECT_NEXT(argc, argv);
82				  if(!strcmp(argv[0], "dev")) {
83					EXPECT_NEXT(argc, argv);
84					rt.rt_dev = argv[0];
85					if (ioctl(s, SIOCADDRT, &rt) < 0){
86					  die("SIOCADDRT");
87					}
88				  }
89				}
90			}
91        }
92		ADVANCE(argc, argv);
93    }
94
95    return 0;
96}
97
98