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 #include "fwd_utils.h"
  23
  24 struct fwd_addr * fwd_get_addrs(int fd, int family)
  25 {
  26         struct {
  27                   struct nlmsghdr n;
  28                   struct ifaddrmsg r;
  29         } req;
  30
  31         int offlen;
  32         int rtattrlen;
  33         int dump_done;
  34         char buf[16384];
  35
  36         struct rtattr *rta;
  37         struct rtattr *rtatp;
  38         struct nlmsghdr *nlmp;
  39         struct ifaddrmsg *rtmp;
  40
  41         struct fwd_addr *head, *entry;
  42
  43         /* Build request */
  44         memset(&req, 0, sizeof(req));
  45         req.n.nlmsg_len   = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
  46         req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
  47         req.n.nlmsg_type  = RTM_GETADDR;
  48         req.r.ifa_family  = family;
  49
  50         rta = (struct rtattr *)(((char *)&req) + NLMSG_ALIGN(req.n.nlmsg_len));
  51         rta->rta_len = RTA_LENGTH(family == AF_INET ? 4 : 16);
  52
  53         head = entry = NULL;
  54
  55         /* Send request */
  56         if( send(fd, &req, sizeof(req), 0) <= 0 )
  57                 goto error;
  58
  59         /* Receive responses */
  60         for( dump_done = 0; !dump_done; )
  61         {
  62                 if( (offlen = recv(fd, buf, sizeof(buf), 0)) <= 0 )
  63                         goto error;
  64
  65                 /* Parse message */
  66                 for(nlmp = (struct nlmsghdr *)buf; offlen > sizeof(*nlmp);)
  67                 {
  68                         /* Dump finished? */
  69                         if( nlmp->nlmsg_type == NLMSG_DONE )
  70                         {
  71                                 dump_done = 1;
  72                                 break;
  73                         }
  74
  75                         int len = nlmp->nlmsg_len;
  76                         int req_len = len - sizeof(*nlmp);
  77
  78                         if( req_len<0 || len>offlen )
  79                                 goto error;
  80
  81                         if( !NLMSG_OK(nlmp, offlen) )
  82                                 goto error;
  83
  84                         rtmp  = (struct ifaddrmsg *) NLMSG_DATA(nlmp);
  85                         rtatp = (struct rtattr *) IFA_RTA(rtmp);
  86
  87                         if( !(entry = fwd_alloc_ptr(struct fwd_addr)) )
  88                                 goto error;
  89
  90                         entry->index = rtmp->ifa_index;
  91                         if_indextoname(rtmp->ifa_index, (char *)&entry->ifname);
  92
  93                         rtattrlen = IFA_PAYLOAD(nlmp);
  94
  95                         for( ; RTA_OK(rtatp, rtattrlen); rtatp = RTA_NEXT(rtatp, rtattrlen) )
  96                         {
  97                                 if( rtatp->rta_type == IFA_ADDRESS )
  98                                 {
  99                                         memcpy(&entry->ipaddr.addr, (char *) RTA_DATA(rtatp), rtatp->rta_len);
 100                                         entry->ipaddr.prefix = rtmp->ifa_prefixlen;
 101                                         entry->family = family;
 102                                 }
 103                                 else if( rtatp->rta_type == IFA_LABEL)
 104                                 {
 105                                         memcpy(&entry->label, (char *) RTA_DATA(rtatp), rtatp->rta_len);
 106                                 }
 107                         }
 108
 109                         entry->next = head;
 110                         head = entry;
 111
 112                         offlen -= NLMSG_ALIGN(len);
 113                         nlmp = (struct nlmsghdr*)((char*)nlmp + NLMSG_ALIGN(len));
 114                 }
 115         }
 116
 117         return head;
 118
 119
 120         error:
 121
 122         fwd_free_addrs(head);
 123         head = entry = NULL;
 124
 125         return NULL;
 126 }
 127
 128 struct fwd_cidr * fwd_lookup_addr(struct fwd_addr *head, const char *ifname)
 129 {
 130         struct fwd_addr *entry;
 131
 132         for( entry = head; entry; entry = entry->next )
 133                 if( !strncmp(entry->ifname, ifname, IFNAMSIZ) )
 134                         return &entry->ipaddr;
 135
 136         return NULL;
 137 }
 138
 139 void fwd_free_addrs(struct fwd_addr *head)
 140 {
 141         struct fwd_addr *entry = head;
 142
 143         while( entry != NULL )
 144         {
 145                 head = entry->next;
 146                 free(entry);
 147                 entry = head;
 148         }
 149
 150         head = entry = NULL;
 151 }
 152
 153 struct fwd_addr * fwd_append_addrs(struct fwd_addr *head, struct fwd_addr *add)
 154 {
 155         struct fwd_addr *entry = head;
 156
 157         while( entry->next != NULL )
 158                 entry = entry->next;
 159
 160         return (entry->next = add);
 161 }
 162