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