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Annotation of embedaddon/iftop/addrs_ioctl.c, revision 1.1.1.1

1.1       misho       1: /*
                      2:  * addrs_ioctl.c:
                      3:  *
                      4:  * Provides the get_addrs_ioctl() function for use on systems that
                      5:  * support a simple socket ioctl for acquiring low-level ethernet
                      6:  * information about interfaces.
                      7:  *
                      8:  */
                      9: 
                     10: #include <stdio.h>
                     11: #include <stdlib.h>
                     12: #include <unistd.h>
                     13: #include <string.h>
                     14: 
                     15: #include <sys/types.h>
                     16: #include <sys/ioctl.h>
                     17: #include <sys/socket.h>
                     18: #include <net/if.h>
                     19: #include <netinet/in.h>
                     20: 
                     21: #if defined __FreeBSD__ || defined __OpenBSD__ || defined __APPLE__
                     22: #include <sys/param.h>
                     23: #include <sys/sysctl.h>
                     24: #include <net/if_dl.h>
                     25: #endif
                     26: 
                     27: #include "iftop.h"
                     28: 
                     29: /*
                     30:  * This function identifies the IP address and ethernet address for the requested
                     31:  * interface
                     32:  *
                     33:  * This function returns -1 on catastrophic failure, or a bitwise OR of the
                     34:  * following values:
                     35:  *
                     36:  * 1 - Was able to get the ethernet address
                     37:  * 2 - Was able to get the IP address
                     38:  *
                     39:  * This function should return 3 if all information was found
                     40:  */
                     41: 
                     42: int
                     43: get_addrs_ioctl(char *interface, char if_hw_addr[], struct in_addr *if_ip_addr)
                     44: {
                     45:   int s;
                     46:   struct ifreq ifr = {};
                     47:   int got_hw_addr = 0;
                     48:   int got_ip_addr = 0;
                     49: 
                     50:   /* -- */
                     51: 
                     52:   s = socket(PF_INET, SOCK_DGRAM, 0); /* any sort of IP socket will do */
                     53: 
                     54:   if (s == -1) {
                     55:     perror("socket");
                     56:     return -1;
                     57:   }
                     58: 
                     59:   fprintf(stderr,"interface: %s\n", interface);
                     60: 
                     61:   memset(if_hw_addr, 0, 6);
                     62:   strncpy(ifr.ifr_name, interface, IFNAMSIZ);
                     63: 
                     64: #ifdef SIOCGIFHWADDR
                     65:   if (ioctl(s, SIOCGIFHWADDR, &ifr) < 0) {
                     66:     fprintf(stderr, "Error getting hardware address for interface: %s\n", interface); 
                     67:     perror("ioctl(SIOCGIFHWADDR)");
                     68:   }
                     69:   else {
                     70:     memcpy(if_hw_addr, ifr.ifr_hwaddr.sa_data, 6);
                     71:     got_hw_addr = 1;
                     72:   }
                     73: #else
                     74: #if defined __FreeBSD__ || defined __OpenBSD__ || defined __APPLE__
                     75:   {
                     76:     int sysctlparam[6] = {CTL_NET, PF_ROUTE, 0, 0, NET_RT_IFLIST, 0};
                     77:     size_t needed = 0;
                     78:     char *buf = NULL;
                     79:     struct if_msghdr *msghdr = NULL;
                     80:     sysctlparam[5] = if_nametoindex(interface);
                     81:     if (sysctlparam[5] == 0) {
                     82:       fprintf(stderr, "Error getting hardware address for interface: %s\n", interface);
                     83:       goto ENDHWADDR;
                     84:     }
                     85:     if (sysctl(sysctlparam, 6, NULL, &needed, NULL, 0) < 0) {
                     86:       fprintf(stderr, "Error getting hardware address for interface: %s\n", interface);
                     87:       goto ENDHWADDR;
                     88:     }
                     89:     if ((buf = malloc(needed)) == NULL) {
                     90:       fprintf(stderr, "Error getting hardware address for interface: %s\n", interface);
                     91:       goto ENDHWADDR;
                     92:     }
                     93:     if (sysctl(sysctlparam, 6, buf, &needed, NULL, 0) < 0) {
                     94:       fprintf(stderr, "Error getting hardware address for interface: %s\n", interface);
                     95:       free(buf);
                     96:       goto ENDHWADDR;
                     97:     }
                     98:     msghdr = (struct if_msghdr *) buf;
                     99:     memcpy(if_hw_addr, LLADDR((struct sockaddr_dl *)(buf + sizeof(struct if_msghdr) - sizeof(struct if_data) + sizeof(struct if_data))), 6);
                    100:     free(buf);
                    101:     got_hw_addr = 1;
                    102: 
                    103:   ENDHWADDR:
                    104:     1; /* compiler whines if there is a label at the end of a block...*/
                    105:   }
                    106: #else
                    107:   fprintf(stderr, "Cannot obtain hardware address on this platform\n");
                    108: #endif
                    109: #endif
                    110:   
                    111:   /* Get the IP address of the interface */
                    112: #ifdef SIOCGIFADDR
                    113:   (*(struct sockaddr_in *) &ifr.ifr_addr).sin_family = AF_INET;
                    114:   if (ioctl(s, SIOCGIFADDR, &ifr) < 0) {
                    115:     fprintf(stderr, "Unable to get IP address for interface: %s\n", interface); 
                    116:     perror("ioctl(SIOCGIFADDR)");
                    117:   }
                    118:   else {
                    119:     memcpy(if_ip_addr, &((*(struct sockaddr_in *) &ifr.ifr_addr).sin_addr), sizeof(struct in_addr));
                    120:     got_ip_addr = 2;
                    121:   }
                    122: #else
                    123:   fprintf(stderr, "Cannot obtain IP address on this platform\n");
                    124: #endif
                    125:   
                    126:   close(s);
                    127: 
                    128:   return got_hw_addr + got_ip_addr;
                    129: }