426 lines
10 KiB
C
426 lines
10 KiB
C
/*
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* Copyright (c) 1992 Regents of the University of California.
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* All rights reserved.
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*
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* This software was developed by the Computer Systems Engineering group
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* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
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* contributed to Berkeley.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* The send and receive functions were originally implemented in udp.c and
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* moved here. Also it is likely some more cleanup can be done, especially
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* once we will implement the support for tcp.
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*/
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#include <sys/cdefs.h>
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/queue.h>
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#include <string.h>
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#include <net/if.h>
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#include <netinet/in.h>
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#include <netinet/if_ether.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#include <netinet/udp.h>
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#include <netinet/udp_var.h>
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#include "stand.h"
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#include "net.h"
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typedef STAILQ_HEAD(ipqueue, ip_queue) ip_queue_t;
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struct ip_queue {
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void *ipq_pkt;
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struct ip *ipq_hdr;
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STAILQ_ENTRY(ip_queue) ipq_next;
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};
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/*
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* Fragment re-assembly queue.
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*/
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struct ip_reasm {
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struct in_addr ip_src;
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struct in_addr ip_dst;
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uint16_t ip_id;
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uint8_t ip_proto;
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uint8_t ip_ttl;
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size_t ip_total_size;
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ip_queue_t ip_queue;
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void *ip_pkt;
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struct ip *ip_hdr;
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STAILQ_ENTRY(ip_reasm) ip_next;
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};
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STAILQ_HEAD(ire_list, ip_reasm) ire_list = STAILQ_HEAD_INITIALIZER(ire_list);
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/* Caller must leave room for ethernet and ip headers in front!! */
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ssize_t
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sendip(struct iodesc *d, void *pkt, size_t len, uint8_t proto)
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{
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ssize_t cc;
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struct ip *ip;
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u_char *ea;
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#ifdef NET_DEBUG
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if (debug) {
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printf("sendip: proto: %x d=%p called.\n", proto, (void *)d);
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if (d) {
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printf("saddr: %s:%d",
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inet_ntoa(d->myip), ntohs(d->myport));
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printf(" daddr: %s:%d\n",
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inet_ntoa(d->destip), ntohs(d->destport));
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}
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}
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#endif
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ip = (struct ip *)pkt - 1;
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len += sizeof(*ip);
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bzero(ip, sizeof(*ip));
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ip->ip_v = IPVERSION; /* half-char */
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ip->ip_hl = sizeof(*ip) >> 2; /* half-char */
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ip->ip_len = htons(len);
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ip->ip_p = proto; /* char */
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ip->ip_ttl = IPDEFTTL; /* char */
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ip->ip_src = d->myip;
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ip->ip_dst = d->destip;
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ip->ip_sum = in_cksum(ip, sizeof(*ip)); /* short, but special */
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if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
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netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
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ea = arpwhohas(d, ip->ip_dst);
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else
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ea = arpwhohas(d, gateip);
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cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
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if (cc == -1)
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return (-1);
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if (cc != len)
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panic("sendip: bad write (%zd != %zd)", cc, len);
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return (cc - sizeof(*ip));
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}
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static void
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ip_reasm_free(struct ip_reasm *ipr)
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{
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struct ip_queue *ipq;
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while ((ipq = STAILQ_FIRST(&ipr->ip_queue)) != NULL) {
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STAILQ_REMOVE_HEAD(&ipr->ip_queue, ipq_next);
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free(ipq->ipq_pkt);
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free(ipq);
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}
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free(ipr->ip_pkt);
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free(ipr);
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}
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static int
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ip_reasm_add(struct ip_reasm *ipr, void *pkt, struct ip *ip)
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{
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struct ip_queue *ipq, *prev, *p;
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if ((ipq = calloc(1, sizeof (*ipq))) == NULL)
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return (1);
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ipq->ipq_pkt = pkt;
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ipq->ipq_hdr = ip;
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prev = NULL;
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STAILQ_FOREACH(p, &ipr->ip_queue, ipq_next) {
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if ((ntohs(p->ipq_hdr->ip_off) & IP_OFFMASK) <
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(ntohs(ip->ip_off) & IP_OFFMASK)) {
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prev = p;
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continue;
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}
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if (prev == NULL)
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break;
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STAILQ_INSERT_AFTER(&ipr->ip_queue, prev, ipq, ipq_next);
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return (0);
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}
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STAILQ_INSERT_HEAD(&ipr->ip_queue, ipq, ipq_next);
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return (0);
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}
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/*
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* Receive a IP packet and validate it is for us.
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*/
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static ssize_t
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readipv4(struct iodesc *d, void **pkt, void **payload, time_t tleft,
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uint8_t proto)
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{
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ssize_t n;
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size_t hlen;
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struct ether_header *eh;
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struct ip *ip;
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struct udphdr *uh;
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uint16_t etype; /* host order */
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char *ptr;
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struct ip_reasm *ipr;
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struct ip_queue *ipq, *last;
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#ifdef NET_DEBUG
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if (debug)
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printf("readip: called\n");
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#endif
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ip = NULL;
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ptr = NULL;
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n = readether(d, (void **)&ptr, (void **)&ip, tleft, &etype);
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if (n == -1 || n < sizeof(*ip) + sizeof(*uh)) {
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free(ptr);
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return (-1);
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}
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/* Ethernet address checks now in readether() */
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/* Need to respond to ARP requests. */
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if (etype == ETHERTYPE_ARP) {
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struct arphdr *ah = (void *)ip;
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if (ah->ar_op == htons(ARPOP_REQUEST)) {
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/* Send ARP reply */
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arp_reply(d, ah);
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}
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free(ptr);
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errno = EAGAIN; /* Call me again. */
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return (-1);
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}
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if (etype != ETHERTYPE_IP) {
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#ifdef NET_DEBUG
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if (debug)
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printf("readip: not IP. ether_type=%x\n", etype);
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#endif
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free(ptr);
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return (-1);
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}
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/* Check ip header */
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if (ip->ip_v != IPVERSION || /* half char */
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ip->ip_p != proto) {
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#ifdef NET_DEBUG
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if (debug) {
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printf("readip: IP version or proto. ip_v=%d ip_p=%d\n",
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ip->ip_v, ip->ip_p);
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}
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#endif
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free(ptr);
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return (-1);
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}
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hlen = ip->ip_hl << 2;
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if (hlen < sizeof(*ip) ||
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in_cksum(ip, hlen) != 0) {
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#ifdef NET_DEBUG
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if (debug)
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printf("readip: short hdr or bad cksum.\n");
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#endif
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free(ptr);
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return (-1);
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}
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if (n < ntohs(ip->ip_len)) {
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#ifdef NET_DEBUG
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if (debug)
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printf("readip: bad length %d < %d.\n",
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(int)n, ntohs(ip->ip_len));
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#endif
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free(ptr);
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return (-1);
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}
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if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
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#ifdef NET_DEBUG
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if (debug) {
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printf("readip: bad saddr %s != ", inet_ntoa(d->myip));
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printf("%s\n", inet_ntoa(ip->ip_dst));
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}
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#endif
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free(ptr);
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return (-1);
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}
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/* Unfragmented packet. */
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if ((ntohs(ip->ip_off) & IP_MF) == 0 &&
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(ntohs(ip->ip_off) & IP_OFFMASK) == 0) {
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uh = (struct udphdr *)((uintptr_t)ip + sizeof (*ip));
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/* If there were ip options, make them go away */
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if (hlen != sizeof(*ip)) {
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bcopy(((u_char *)ip) + hlen, uh, uh->uh_ulen - hlen);
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ip->ip_len = htons(sizeof(*ip));
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n -= hlen - sizeof(*ip);
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}
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n = (n > (ntohs(ip->ip_len) - sizeof(*ip))) ?
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ntohs(ip->ip_len) - sizeof(*ip) : n;
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*pkt = ptr;
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*payload = (void *)((uintptr_t)ip + sizeof(*ip));
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return (n);
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}
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STAILQ_FOREACH(ipr, &ire_list, ip_next) {
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if (ipr->ip_src.s_addr == ip->ip_src.s_addr &&
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ipr->ip_dst.s_addr == ip->ip_dst.s_addr &&
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ipr->ip_id == ip->ip_id &&
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ipr->ip_proto == ip->ip_p)
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break;
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}
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/* Allocate new reassembly entry */
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if (ipr == NULL) {
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if ((ipr = calloc(1, sizeof (*ipr))) == NULL) {
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free(ptr);
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return (-1);
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}
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ipr->ip_src = ip->ip_src;
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ipr->ip_dst = ip->ip_dst;
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ipr->ip_id = ip->ip_id;
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ipr->ip_proto = ip->ip_p;
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ipr->ip_ttl = MAXTTL;
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STAILQ_INIT(&ipr->ip_queue);
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STAILQ_INSERT_TAIL(&ire_list, ipr, ip_next);
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}
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if (ip_reasm_add(ipr, ptr, ip) != 0) {
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STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
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free(ipr);
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free(ptr);
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return (-1);
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}
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if ((ntohs(ip->ip_off) & IP_MF) == 0) {
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ipr->ip_total_size = (8 * (ntohs(ip->ip_off) & IP_OFFMASK));
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ipr->ip_total_size += n + sizeof (*ip);
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ipr->ip_total_size += sizeof (struct ether_header);
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ipr->ip_pkt = malloc(ipr->ip_total_size + 2);
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if (ipr->ip_pkt == NULL) {
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STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
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ip_reasm_free(ipr);
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return (-1);
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}
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}
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/*
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* If we do not have re-assembly buffer ipr->ip_pkt, we are still
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* missing fragments, so just restart the read.
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*/
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if (ipr->ip_pkt == NULL) {
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errno = EAGAIN;
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return (-1);
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}
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/*
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* Walk the packet list in reassembly queue, if we got all the
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* fragments, build the packet.
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*/
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n = 0;
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last = NULL;
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STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
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if ((ntohs(ipq->ipq_hdr->ip_off) & IP_OFFMASK) != n / 8) {
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STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
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ip_reasm_free(ipr);
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return (-1);
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}
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n += ntohs(ipq->ipq_hdr->ip_len) - (ipq->ipq_hdr->ip_hl << 2);
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last = ipq;
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}
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if ((ntohs(last->ipq_hdr->ip_off) & IP_MF) != 0) {
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errno = EAGAIN;
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return (-1);
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}
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ipq = STAILQ_FIRST(&ipr->ip_queue);
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/* Fabricate ethernet header */
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eh = (struct ether_header *)((uintptr_t)ipr->ip_pkt + 2);
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bcopy((void *)((uintptr_t)ipq->ipq_pkt + 2), eh, sizeof (*eh));
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/* Fabricate IP header */
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ipr->ip_hdr = (struct ip *)((uintptr_t)eh + sizeof (*eh));
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bcopy(ipq->ipq_hdr, ipr->ip_hdr, sizeof (*ipr->ip_hdr));
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ipr->ip_hdr->ip_hl = sizeof (*ipr->ip_hdr) >> 2;
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ipr->ip_hdr->ip_len = htons(n);
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ipr->ip_hdr->ip_sum = 0;
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ipr->ip_hdr->ip_sum = in_cksum(ipr->ip_hdr, sizeof (*ipr->ip_hdr));
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n = 0;
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ptr = (char *)((uintptr_t)ipr->ip_hdr + sizeof (*ipr->ip_hdr));
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STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
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char *data;
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size_t len;
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hlen = ipq->ipq_hdr->ip_hl << 2;
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len = ntohs(ipq->ipq_hdr->ip_len) - hlen;
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data = (char *)((uintptr_t)ipq->ipq_hdr + hlen);
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bcopy(data, ptr + n, len);
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n += len;
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}
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*pkt = ipr->ip_pkt;
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ipr->ip_pkt = NULL; /* Avoid free from ip_reasm_free() */
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*payload = ptr;
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/* Clean up the reassembly list */
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while ((ipr = STAILQ_FIRST(&ire_list)) != NULL) {
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STAILQ_REMOVE_HEAD(&ire_list, ip_next);
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ip_reasm_free(ipr);
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}
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return (n);
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}
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/*
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* Receive a IP packet.
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*/
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ssize_t
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readip(struct iodesc *d, void **pkt, void **payload, time_t tleft,
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uint8_t proto)
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{
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time_t t;
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ssize_t ret = -1;
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t = getsecs();
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while ((getsecs() - t) < tleft) {
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errno = 0;
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ret = readipv4(d, pkt, payload, tleft, proto);
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if (ret >= 0)
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return (ret);
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/* Bubble up the error if it wasn't successful */
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if (errno != EAGAIN)
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return (-1);
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}
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/* We've exhausted tleft; timeout */
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errno = ETIMEDOUT;
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return (-1);
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}
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