summaryrefslogtreecommitdiff
path: root/usr.sbin/dhcp/common/packet.c
diff options
context:
space:
mode:
Diffstat (limited to 'usr.sbin/dhcp/common/packet.c')
-rw-r--r--usr.sbin/dhcp/common/packet.c136
1 files changed, 66 insertions, 70 deletions
diff --git a/usr.sbin/dhcp/common/packet.c b/usr.sbin/dhcp/common/packet.c
index 5b136c394ff..499f20cb1bf 100644
--- a/usr.sbin/dhcp/common/packet.c
+++ b/usr.sbin/dhcp/common/packet.c
@@ -3,7 +3,7 @@
Packet assembly code, originally contributed by Archie Cobbs. */
/*
- * Copyright (c) 1995, 1996 The Internet Software Consortium.
+ * Copyright (c) 1995, 1996, 1999 The Internet Software Consortium.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -40,18 +40,11 @@
* Enterprises, see ``http://www.vix.com''.
*/
-#ifndef lint
-static char copyright[] =
-"$Id: packet.c,v 1.3 2001/01/14 23:01:19 angelos Exp $ Copyright (c) 1996 The Internet Software Consortium. All rights reserved.\n";
-#endif /* not lint */
-
#include "dhcpd.h"
-#if defined (PACKET_ASSEMBLY) || defined (PACKET_DECODING)
-#include "includes/netinet/ip.h"
-#include "includes/netinet/udp.h"
-#include "includes/netinet/if_ether.h"
-#endif /* PACKET_ASSEMBLY || PACKET_DECODING */
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/udp.h>
/* Compute the easy part of the checksum on a range of bytes. */
@@ -60,7 +53,7 @@ u_int32_t checksum (buf, nbytes, sum)
unsigned nbytes;
u_int32_t sum;
{
- unsigned i;
+ int i;
#ifdef DEBUG_CHECKSUM
debug ("checksum (%x %d %x)", buf, nbytes, sum);
@@ -92,7 +85,7 @@ u_int32_t checksum (buf, nbytes, sum)
return sum;
}
-/* Finish computing the checksum, and then put it into network byte order. */
+/* Finish computing the sum, and then put it into network byte order. */
u_int32_t wrapsum (sum)
u_int32_t sum;
@@ -103,7 +96,7 @@ u_int32_t wrapsum (sum)
sum = ~sum & 0xFFFF;
#ifdef DEBUG_CHECKSUM_VERBOSE
- log_debug ("sum = %x", sum);
+ debug ("sum = %x", sum);
#endif
#ifdef DEBUG_CHECKSUM
@@ -112,7 +105,6 @@ u_int32_t wrapsum (sum)
return htons(sum);
}
-#ifdef PACKET_ASSEMBLY
/* Assemble an hardware header... */
/* XXX currently only supports ethernet; doesn't check for other types. */
@@ -122,26 +114,13 @@ void assemble_hw_header (interface, buf, bufix, to)
int *bufix;
struct hardware *to;
{
- struct ether_header eh;
-
- if (to && to -> hlen == 6) /* XXX */
- memcpy (eh.ether_dhost, to -> haddr, sizeof eh.ether_dhost);
- else
- memset (eh.ether_dhost, 0xff, sizeof (eh.ether_dhost));
- if (interface -> hw_address.hlen == sizeof (eh.ether_shost))
- memcpy (eh.ether_shost, interface -> hw_address.haddr,
- sizeof (eh.ether_shost));
+#if defined (HAVE_TR_SUPPORT)
+ if (interface -> hw_address.htype == HTYPE_IEEE802)
+ assemble_tr_header (interface, buf, bufix, to);
else
- memset (eh.ether_shost, 0x00, sizeof (eh.ether_shost));
-
-#ifdef BROKEN_FREEBSD_BPF /* Fixed in FreeBSD 2.2 */
- eh.ether_type = ETHERTYPE_IP;
-#else
- eh.ether_type = htons (ETHERTYPE_IP);
#endif
+ assemble_ethernet_header (interface, buf, bufix, to);
- memcpy (&buf [*bufix], &eh, sizeof eh);
- *bufix += sizeof eh;
}
/* UDP header and IP header assembled together for convenience. */
@@ -153,7 +132,7 @@ void assemble_udp_ip_header (interface, buf, bufix,
int *bufix;
u_int32_t from;
u_int32_t to;
- u_int16_t port;
+ unsigned int port;
unsigned char *data;
int len;
{
@@ -189,7 +168,6 @@ void assemble_udp_ip_header (interface, buf, bufix,
/* Compute UDP checksums, including the ``pseudo-header'', the UDP
header and the data. */
-#if 1
udp.uh_sum =
wrapsum (checksum ((unsigned char *)&udp, sizeof udp,
checksum (data, len,
@@ -199,17 +177,13 @@ void assemble_udp_ip_header (interface, buf, bufix,
IPPROTO_UDP +
(u_int32_t)
ntohs (udp.uh_ulen)))));
-#endif
/* Copy the udp header into the buffer... */
memcpy (&buf [*bufix], &udp, sizeof udp);
*bufix += sizeof udp;
}
-#endif /* PACKET_ASSEMBLY */
-#ifdef PACKET_DECODING
/* Decode a hardware header... */
-/* XXX currently only supports ethernet; doesn't check for other types. */
ssize_t decode_hw_header (interface, buf, bufix, from)
struct interface_info *interface;
@@ -217,55 +191,57 @@ ssize_t decode_hw_header (interface, buf, bufix, from)
int bufix;
struct hardware *from;
{
- struct ether_header eh;
-
- memcpy (&eh, buf + bufix, sizeof eh);
-
-#ifdef USERLAND_FILTER
- if (ntohs (eh.ether_type) != ETHERTYPE_IP)
- return -1;
+#if defined (HAVE_TR_SUPPORT)
+ if (interface -> hw_address.htype == HTYPE_IEEE802)
+ return decode_tr_header (interface, buf, bufix, from);
+ else
#endif
- memcpy (from -> haddr, eh.ether_shost, sizeof (eh.ether_shost));
- from -> htype = ARPHRD_ETHER;
- from -> hlen = sizeof eh.ether_shost;
-
- return sizeof eh;
+ return decode_ethernet_header (interface, buf, bufix, from);
}
/* UDP header and IP header decoded together for convenience. */
-ssize_t decode_udp_ip_header (interface, buf, bufix, from, data, len)
+ssize_t decode_udp_ip_header (interface, buf, bufix, from, data, buflen)
struct interface_info *interface;
unsigned char *buf;
int bufix;
struct sockaddr_in *from;
unsigned char *data;
- int len;
+ int buflen;
{
struct ip *ip;
struct udphdr *udp;
u_int32_t ip_len = (buf [bufix] & 0xf) << 2;
+ u_int32_t sum, usum;
+ static int ip_packets_seen;
+ static int ip_packets_bad_checksum;
+ static int udp_packets_seen;
+ static int udp_packets_bad_checksum;
+ static int udp_packets_length_checked;
+ static int udp_packets_length_overflow;
+ int len = 0;
ip = (struct ip *)(buf + bufix);
udp = (struct udphdr *)(buf + bufix + ip_len);
-#ifdef USERLAND_FILTER
- /* Is it a UDP packet? */
- if (ip -> ip_p != IPPROTO_UDP)
- return -1;
-
- /* Is it to the port we're serving? */
- if (udp -> uh_dport != local_port)
- return -1;
-#endif /* USERLAND_FILTER */
-
/* Check the IP header checksum - it should be zero. */
+ ++ip_packets_seen;
if (wrapsum (checksum (buf + bufix, ip_len, 0))) {
- note ("Bad IP checksum: %x",
- wrapsum (checksum (buf + bufix, sizeof *ip, 0)));
+ ++ip_packets_bad_checksum;
+ if (ip_packets_seen > 4 &&
+ (ip_packets_seen / ip_packets_bad_checksum) < 2) {
+ note ("%d bad IP checksums seen in %d packets",
+ ip_packets_bad_checksum, ip_packets_seen);
+ ip_packets_seen = ip_packets_bad_checksum = 0;
+ }
return -1;
}
+ /* Check the IP packet length. */
+ if (ntohs (ip -> ip_len) != buflen)
+ debug ("ip length %d disagrees with bytes received %d.",
+ ntohs (ip -> ip_len), buflen);
+
/* Copy out the IP source address... */
memcpy (&from -> sin_addr, &ip -> ip_src, 4);
@@ -275,10 +251,25 @@ ssize_t decode_udp_ip_header (interface, buf, bufix, from, data, len)
if (!data) {
data = buf + bufix + ip_len + sizeof *udp;
- len -= ip_len + sizeof *udp;
+ len = ntohs (udp -> uh_ulen) - sizeof *udp;
+ ++udp_packets_length_checked;
+ if (len + data > buf + bufix + buflen) {
+ ++udp_packets_length_overflow;
+ if (udp_packets_length_checked > 4 &&
+ (udp_packets_length_checked /
+ udp_packets_length_overflow) < 2) {
+ note ("%d udp packets in %d too long - dropped",
+ udp_packets_length_overflow,
+ udp_packets_length_checked);
+ udp_packets_length_overflow =
+ udp_packets_length_checked = 0;
+ }
+ return -1;
+ }
+ if (len + data != buf + bufix + buflen)
+ debug ("accepting packet with data after udp payload.");
}
-#if 0
usum = udp -> uh_sum;
udp -> uh_sum = 0;
@@ -286,20 +277,25 @@ ssize_t decode_udp_ip_header (interface, buf, bufix, from, data, len)
checksum (data, len,
checksum ((unsigned char *)
&ip -> ip_src,
- sizeof ip -> ip_src,
+ 2 * sizeof ip -> ip_src,
IPPROTO_UDP +
(u_int32_t)
ntohs (udp -> uh_ulen)))));
+ udp_packets_seen++;
if (usum && usum != sum) {
- note ("Bad udp checksum: %x %x", usum, sum);
+ udp_packets_bad_checksum++;
+ if (udp_packets_seen > 4 &&
+ (udp_packets_seen / udp_packets_bad_checksum) < 2) {
+ note ("%d bad udp checksums in %d packets",
+ udp_packets_bad_checksum, udp_packets_seen);
+ udp_packets_seen = udp_packets_bad_checksum = 0;
+ }
return -1;
}
-#endif
/* Copy out the port... */
memcpy (&from -> sin_port, &udp -> uh_sport, sizeof udp -> uh_sport);
return ip_len + sizeof *udp;
}
-#endif /* PACKET_DECODING */
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-12 07:45:19 +0000