contrib/fwd/src/fwd_addr.c

   1 /*
   2  * fwd - OpenWrt firewall daemon - rtnetlink communication
   3  *
   4  *   Copyright (C) 2009 Jo-Philipp Wich <xm@subsignal.org>
   5  *
   6  * The fwd program is free software: you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License version 2
   8  * as published by the Free Software Foundation.
   9  *
  10  * The fwd program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with the fwd program. If not, see http://www.gnu.org/licenses/.
  17  */
  18
  19
  20 #include "fwd.h"
  21 #include "fwd_addr.h"
  22
  23 struct fwd_addr_list * fwd_get_addrs(int fd, int family)
  24 {
  25         struct {
  26                   struct nlmsghdr n;
  27                   struct ifaddrmsg r;
  28         } req;
  29
  30         int offlen;
  31         int rtattrlen;
  32         int dump_done;
  33         char buf[16384];
  34
  35         struct rtattr *rta;
  36         struct rtattr *rtatp;
  37         struct nlmsghdr *nlmp;
  38         struct ifaddrmsg *rtmp;
  39
  40         struct fwd_addr_list *head, *entry;
  41
  42         /* Build request */
  43         memset(&req, 0, sizeof(req));
  44         req.n.nlmsg_len   = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
  45         req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
  46         req.n.nlmsg_type  = RTM_GETADDR;
  47         req.r.ifa_family  = family;
  48
  49         rta = (struct rtattr *)(((char *)&req) + NLMSG_ALIGN(req.n.nlmsg_len));
  50         rta->rta_len = RTA_LENGTH(family == AF_INET ? 4 : 16);
  51
  52         head = entry = NULL;
  53
  54         /* Send request */
  55         if( send(fd, &req, sizeof(req), 0) <= 0 )
  56                 goto error;
  57
  58         /* Receive responses */
  59         for( dump_done = 0; !dump_done; )
  60         {
  61                 if( (offlen = recv(fd, buf, sizeof(buf), 0)) <= 0 )
  62                         goto error;
  63
  64                 /* Parse message */
  65                 for(nlmp = (struct nlmsghdr *)buf; offlen > sizeof(*nlmp);)
  66                 {
  67                         /* Dump finished? */
  68                         if( nlmp->nlmsg_type == NLMSG_DONE )
  69                         {
  70                                 dump_done = 1;
  71                                 break;
  72                         }
  73
  74                         int len = nlmp->nlmsg_len;
  75                         int req_len = len - sizeof(*nlmp);
  76
  77                         if( req_len<0 || len>offlen )
  78                                 goto error;
  79
  80                         if( !NLMSG_OK(nlmp, offlen) )
  81                                 goto error;
  82
  83                         rtmp  = (struct ifaddrmsg *) NLMSG_DATA(nlmp);
  84                         rtatp = (struct rtattr *) IFA_RTA(rtmp);
  85
  86                         if( !(entry = fwd_alloc_ptr(struct fwd_addr_list)) )
  87                                 goto error;
  88
  89                         entry->index = rtmp->ifa_index;
  90                         if_indextoname(rtmp->ifa_index, (char *)&entry->ifname);
  91
  92                         rtattrlen = IFA_PAYLOAD(nlmp);
  93
  94                         for( ; RTA_OK(rtatp, rtattrlen); rtatp = RTA_NEXT(rtatp, rtattrlen) )
  95                         {
  96                                 if( rtatp->rta_type == IFA_ADDRESS )
  97                                 {
  98                                         memcpy(&entry->ipaddr, (char *) RTA_DATA(rtatp), rtatp->rta_len);
  99                                         entry->prefix = rtmp->ifa_prefixlen;
 100                                         entry->family = family;
 101                                 }
 102                                 else if( rtatp->rta_type == IFA_LABEL)
 103                                 {
 104                                         memcpy(&entry->label, (char *) RTA_DATA(rtatp), rtatp->rta_len);
 105                                 }
 106                         }
 107
 108                         entry->next = head;
 109                         head = entry;
 110
 111                         offlen -= NLMSG_ALIGN(len);
 112                         nlmp = (struct nlmsghdr*)((char*)nlmp + NLMSG_ALIGN(len));
 113                 }
 114         }
 115
 116         return head;
 117
 118
 119         error:
 120
 121         fwd_free_addrs(head);
 122         head = entry = NULL;
 123
 124         return NULL;
 125 }
 126
 127 void fwd_free_addrs(struct fwd_addr_list *head)
 128 {
 129         struct fwd_addr_list *entry = head;
 130
 131         while( entry != NULL )
 132         {
 133                 head = entry->next;
 134                 free(entry);
 135                 entry = head;
 136         }
 137
 138         head = entry = NULL;
 139 }
 140
 141 struct fwd_addr_list * fwd_append_addrs(struct fwd_addr_list *head, struct fwd_addr_list *add)
 142 {
 143         struct fwd_addr_list *entry = head;
 144
 145         while( entry->next != NULL )
 146                 entry = entry->next;
 147
 148         return (entry->next = add);
 149 }
 150