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Annotation of qemu/slirp/arp_table.c, revision 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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