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Annotation of embedaddon/iftop/addrs_ioctl.c, revision 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: }