1 files changed, 288 insertions, 0 deletions
diff --git a/usr.sbin/ospfd/packet.c b/usr.sbin/ospfd/packet.c
new file mode 100644
index 00000000000..b76d9c22db4
--- /dev/null
+++ b/usr.sbin/ospfd/packet.c
@@ -0,0 +1,288 @@
+/*	$OpenBSD: packet.c,v 1.1 2005/01/28 14:05:40 claudio Exp $ */
+
+/*
+ * Copyright (c) 2004, 2005 Esben Norby <esben.norby@ericsson.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <event.h>
+#include <stdlib.h>
+#include <strings.h>
+
+#include "ospfd.h"
+#include "ospf.h"
+#include "log.h"
+#include "ospfe.h"
+
+int		 ip_hdr_sanity_check(const struct ip *, u_int16_t);
+int		 ospf_hdr_sanity_check(const struct ip *,
+		    struct ospf_hdr *, u_int16_t, const struct iface *);
+struct iface	*find_iface(struct ospfd_conf *, struct in_addr);
+
+void
+gen_ospf_hdr(void *buf, struct iface *iface, u_int8_t type)
+{
+	struct ospf_hdr	*ospf_hdr = buf;
+
+	ospf_hdr->version = OSPF_VERSION;
+	ospf_hdr->type = type;
+	ospf_hdr->len = 0;			/* updated later */
+	ospf_hdr->rtr_id = iface->rtr_id.s_addr;
+	ospf_hdr->area_id = iface->area->id.s_addr;
+	ospf_hdr->chksum = 0;			/* updated later */
+	ospf_hdr->auth_type = htons(iface->auth_type);
+}
+
+/* send and receive packets */
+int
+send_packet(struct iface *iface, char *pkt, int len, struct sockaddr_in *dst)
+{
+	if (iface->passive) {
+		log_warnx("send_packet: cannot send packet on passive "
+		    "interface %s", iface->name);
+		return (-1);
+	}
+
+	/* set outgoing interface for multicast traffic */
+	if (IN_MULTICAST(ntohl(dst->sin_addr.s_addr)))
+		if (if_set_mcast(iface) == -1) {
+			log_debug("send_packet: error setting multicast "
+			    "interface, %s", iface->name);
+			return (-1);
+		}
+
+	if (sendto(iface->fd, pkt, len, 0,
+	    (struct sockaddr *)dst, sizeof(*dst)) == -1 ) {
+		log_warnx("send_packet: error sending packet on interface %s",
+		    iface->name);
+		return (-1);
+	}
+
+	return (0);
+}
+
+void
+recv_packet(int fd, short event, void *bula)
+{
+	struct ospfd_conf	*xconf = bula;
+	struct ip		 ip_hdr;
+	struct ospf_hdr		*ospf_hdr;
+	struct iface		*iface;
+	struct nbr		*nbr = NULL;
+	struct in_addr		 addr;
+	char			*buf, *ptr;
+	ssize_t			 r;
+	u_int16_t		 len;
+	int			 l;
+
+	if (event != EV_READ)
+		return;
+
+	/*
+	 * XXX I don't like to allocate a buffer for each packet received
+	 * and freeing that buffer at the end of the function. It would be
+	 * enough to allocate the buffer on startup.
+	 */
+	if ((ptr = buf = calloc(1, READ_BUF_SIZE)) == NULL)
+		fatal("recv_packet");
+
+	if ((r = recvfrom(fd, buf, READ_BUF_SIZE, 0, NULL, NULL)) == -1) {
+		if (errno != EAGAIN) {
+			log_debug("recv_packet: error receiving packet");
+		}
+		goto done;
+	}
+
+	len = (u_int16_t)r;
+
+	/* IP header sanity checks */
+	if (len < sizeof(ip_hdr)) {
+		log_warnx("recv_packet: bad packet size");
+		goto done;
+	}
+	memcpy(&ip_hdr, buf, sizeof(ip_hdr));
+	if ((l = ip_hdr_sanity_check(&ip_hdr, len)) == -1)
+		goto done;
+	buf += l;
+	len -= l;
+
+	/* find a matching interface */
+	if ((iface = find_iface(xconf, ip_hdr.ip_src)) == NULL) {
+		log_debug("recv_packet: cannot find valid interface");
+		goto done;
+	}
+
+	/*
+	 * Packet needs to be sent to AllSPFRouters or AllDRouters
+	 * or to the address of the interface itself.
+	 * AllDRouters is only valid for DR and BDR but this is checked later.
+	 */
+	inet_aton(AllSPFRouters, &addr);
+	if (ip_hdr.ip_dst.s_addr != addr.s_addr) {
+		inet_aton(AllDRouters, &addr);
+		if (ip_hdr.ip_dst.s_addr != addr.s_addr) {
+			if (ip_hdr.ip_dst.s_addr != iface->addr.s_addr) {
+				log_debug("recv_packet: packet sent to wrong "
+				    "address %s, interface %s",
+				    inet_ntoa(ip_hdr.ip_dst), iface->name);
+				goto done;
+			}
+		}
+	}
+
+	/* OSPF header sanity checks */
+	if (len < sizeof(*ospf_hdr)) {
+		log_warnx("recv_packet: bad packet size");
+		goto done;
+	}
+	ospf_hdr = (struct ospf_hdr *)buf;
+
+	if ((l = ospf_hdr_sanity_check(&ip_hdr, ospf_hdr, len, iface)) == -1)
+		goto done;
+
+	buf += sizeof(*ospf_hdr);
+	len = l - sizeof(*ospf_hdr);
+
+	if (ospf_hdr->type != PACKET_TYPE_HELLO)
+		/* find neighbor */
+		if ((nbr = nbr_find_id(iface, ospf_hdr->rtr_id)) == NULL) {
+			log_debug("recv_packet: unknown neighbor ID");
+			goto done;
+		}
+
+	/* switch OSPF packet type */
+	switch (ospf_hdr->type) {
+	case PACKET_TYPE_HELLO:
+		inet_aton(AllDRouters, &addr);
+		if (ip_hdr.ip_dst.s_addr == addr.s_addr) {
+			log_debug("recv_packet: invalid destination IP "
+			     "address");
+			break;
+		}
+
+		recv_hello(iface, ip_hdr.ip_src, ospf_hdr->rtr_id, buf, len);
+		break;
+	case PACKET_TYPE_DD:
+		recv_db_description(nbr, buf, len);
+		break;
+	case PACKET_TYPE_LS_REQUEST:
+		recv_ls_req(nbr, buf, len);
+		break;
+	case PACKET_TYPE_LS_UPDATE:
+		recv_ls_update(nbr, buf, len);
+		break;
+	case PACKET_TYPE_LS_ACK:
+		recv_ls_ack(nbr, buf, len);
+		break;
+	default:
+		log_debug("recv_packet: unknown OSPF packet type, interface %s",
+		    iface->name);
+	}
+done:
+	free(ptr);
+	return;
+}
+
+int
+ip_hdr_sanity_check(const struct ip *ip_hdr, u_int16_t len)
+{
+	if (ntohs(ip_hdr->ip_len) != len) {
+		log_debug("recv_packet: invalid IP packet length %s",
+		    ntohs(ip_hdr->ip_len));
+		return (-1);
+	}
+
+	if (ip_hdr->ip_p != IPPROTO_OSPF)
+		/* this is enforced by the socket itself */
+		fatalx("recv_packet: invalid IP proto");
+
+	return (ip_hdr->ip_hl << 2);
+}
+
+int
+ospf_hdr_sanity_check(const struct ip *ip_hdr, struct ospf_hdr *ospf_hdr,
+    u_int16_t len, const struct iface *iface)
+{
+	struct in_addr		 addr;
+
+	if (ospf_hdr->version != OSPF_VERSION) {
+		log_debug("recv_packet: invalid OSPF version %d",
+		    ospf_hdr->version);
+		return (-1);
+	}
+
+	if (ntohs(ospf_hdr->len) > len ||
+	    len <= sizeof(struct ospf_hdr)) {
+		log_debug("recv_packet: invalid OSPF packet length %d",
+		    ntohs(ospf_hdr->len));
+		return (-1);
+	}
+
+	if (ospf_hdr->area_id != iface->area->id.s_addr) {
+		/* TODO backbone area is allowed for virtual links */ 
+		addr.s_addr = ospf_hdr->area_id;
+		log_debug("recv_packet: invalid area ID %s, interface %s",
+		    inet_ntoa(addr), iface->name);
+		return (-1);
+	}
+
+	if (iface->type == IF_TYPE_BROADCAST || iface->type == IF_TYPE_NBMA) {
+		if (inet_aton(AllDRouters, &addr) == 0)
+			fatalx("recv_packet: inet_aton");
+		if ((ip_hdr->ip_dst.s_addr == addr.s_addr) &&
+		    (iface->state != (IF_STA_DR | IF_STA_BACKUP))) {
+			log_debug("recv_packet: invalid destination IP in "
+			    "state %s, interface %s",
+			    if_state_name(iface->state), iface->name);
+			return (-1);
+		}
+	}
+
+	if (auth_validate(ospf_hdr, iface)) {
+		log_warnx("recv_packet: authentication error, interface %s",
+		    iface->name);
+		return (-1);
+	}
+
+	return (ntohs(ospf_hdr->len));
+}
+
+struct iface *
+find_iface(struct ospfd_conf *xconf, struct in_addr src)
+{
+	struct area	*area = NULL;
+	struct iface	*iface = NULL;
+
+	/* returned interface needs to be active */
+	LIST_FOREACH(area, &xconf->area_list, entry) {
+		LIST_FOREACH(iface, &area->iface_list, entry) {
+			if (iface->fd > 0 && (iface->addr.s_addr &
+			    iface->mask.s_addr) == (src.s_addr &
+			    iface->mask.s_addr) && !iface->passive)
+				return (iface);
+		}
+	}
+
+	return (NULL);
+}