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Annotation of qemu/slirp/arp_table.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * ARP table
                      3:  *
                      4:  * Copyright (c) 2011 AdaCore
                      5:  *
                      6:  * Permission is hereby granted, free of charge, to any person obtaining a copy
                      7:  * of this software and associated documentation files (the "Software"), to deal
                      8:  * in the Software without restriction, including without limitation the rights
                      9:  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                     10:  * copies of the Software, and to permit persons to whom the Software is
                     11:  * furnished to do so, subject to the following conditions:
                     12:  *
                     13:  * The above copyright notice and this permission notice shall be included in
                     14:  * all copies or substantial portions of the Software.
                     15:  *
                     16:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                     17:  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                     18:  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
                     19:  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                     20:  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                     21:  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
                     22:  * THE SOFTWARE.
                     23:  */
                     24: 
                     25: #include "slirp.h"
                     26: 
                     27: void arp_table_add(Slirp *slirp, uint32_t ip_addr, uint8_t ethaddr[ETH_ALEN])
                     28: {
                     29:     const uint32_t broadcast_addr =
                     30:         ~slirp->vnetwork_mask.s_addr | slirp->vnetwork_addr.s_addr;
                     31:     ArpTable *arptbl = &slirp->arp_table;
                     32:     int i;
                     33: 
                     34:     DEBUG_CALL("arp_table_add");
                     35:     DEBUG_ARG("ip = 0x%x", ip_addr);
                     36:     DEBUG_ARGS((dfd, " hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
                     37:                 ethaddr[0], ethaddr[1], ethaddr[2],
                     38:                 ethaddr[3], ethaddr[4], ethaddr[5]));
                     39: 
                     40:     /* Check 0.0.0.0/8 invalid source-only addresses */
                     41:     assert((ip_addr & htonl(~(0xf << 28))) != 0);
                     42: 
                     43:     if (ip_addr == 0xffffffff || ip_addr == broadcast_addr) {
                     44:         /* Do not register broadcast addresses */
                     45:         return;
                     46:     }
                     47: 
                     48:     /* Search for an entry */
                     49:     for (i = 0; i < ARP_TABLE_SIZE; i++) {
                     50:         if (arptbl->table[i].ar_sip == ip_addr) {
                     51:             /* Update the entry */
                     52:             memcpy(arptbl->table[i].ar_sha, ethaddr, ETH_ALEN);
                     53:             return;
                     54:         }
                     55:     }
                     56: 
                     57:     /* No entry found, create a new one */
                     58:     arptbl->table[arptbl->next_victim].ar_sip = ip_addr;
                     59:     memcpy(arptbl->table[arptbl->next_victim].ar_sha,  ethaddr, ETH_ALEN);
                     60:     arptbl->next_victim = (arptbl->next_victim + 1) % ARP_TABLE_SIZE;
                     61: }
                     62: 
                     63: bool arp_table_search(Slirp *slirp, uint32_t ip_addr,
                     64:                       uint8_t out_ethaddr[ETH_ALEN])
                     65: {
                     66:     const uint32_t broadcast_addr =
                     67:         ~slirp->vnetwork_mask.s_addr | slirp->vnetwork_addr.s_addr;
                     68:     ArpTable *arptbl = &slirp->arp_table;
                     69:     int i;
                     70: 
                     71:     DEBUG_CALL("arp_table_search");
                     72:     DEBUG_ARG("ip = 0x%x", ip_addr);
                     73: 
                     74:     /* Check 0.0.0.0/8 invalid source-only addresses */
                     75:     assert((ip_addr & htonl(~(0xf << 28))) != 0);
                     76: 
                     77:     /* If broadcast address */
                     78:     if (ip_addr == 0xffffffff || ip_addr == broadcast_addr) {
                     79:         /* return Ethernet broadcast address */
                     80:         memset(out_ethaddr, 0xff, ETH_ALEN);
                     81:         return 1;
                     82:     }
                     83: 
                     84:     for (i = 0; i < ARP_TABLE_SIZE; i++) {
                     85:         if (arptbl->table[i].ar_sip == ip_addr) {
                     86:             memcpy(out_ethaddr, arptbl->table[i].ar_sha,  ETH_ALEN);
                     87:             DEBUG_ARGS((dfd, " found hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
                     88:                         out_ethaddr[0], out_ethaddr[1], out_ethaddr[2],
                     89:                         out_ethaddr[3], out_ethaddr[4], out_ethaddr[5]));
                     90:             return 1;
                     91:         }
                     92:     }
                     93: 
                     94:     return 0;
                     95: }

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