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authorDavid E. O'Brien <obrien@FreeBSD.org>1999-02-10 09:10:13 +0000
committerDavid E. O'Brien <obrien@FreeBSD.org>1999-02-10 09:10:13 +0000
commitcd2d014aab8332077aba9b0f6e0d06678fbe1aff (patch)
tree238471ef1d73dff2645de45ab083d2123bf56b83 /contrib/isc-dhcp/common/packet.c
downloadsrc-cd2d014aab8332077aba9b0f6e0d06678fbe1aff.tar.gz
src-cd2d014aab8332077aba9b0f6e0d06678fbe1aff.zip
Virgin import of ISC-DHCP v2.0b1pl6vendor/isc-dhcp/2.0b1-pl.6
Notes
Notes: svn path=/vendor/isc-dhcp/dist/; revision=43829 svn path=/vendor/isc-dhcp/2.0b1-pl.6/; revision=43831; tag=vendor/isc-dhcp/2.0b1-pl.6
Diffstat (limited to 'contrib/isc-dhcp/common/packet.c')
-rw-r--r--contrib/isc-dhcp/common/packet.c311
1 files changed, 311 insertions, 0 deletions
diff --git a/contrib/isc-dhcp/common/packet.c b/contrib/isc-dhcp/common/packet.c
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+/* packet.c
+
+ Packet assembly code, originally contributed by Archie Cobbs. */
+
+/*
+ * Copyright (c) 1995, 1996 The Internet Software Consortium.
+ * All rights reserved.
+ *
+ * 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 Internet Software Consortium 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 INTERNET SOFTWARE CONSORTIUM 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 INTERNET SOFTWARE CONSORTIUM 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.
+ *
+ * This software has been written for the Internet Software Consortium
+ * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
+ * Enterprises. To learn more about the Internet Software Consortium,
+ * see ``http://www.vix.com/isc''. To learn more about Vixie
+ * Enterprises, see ``http://www.vix.com''.
+ */
+
+#ifndef lint
+static char copyright[] =
+"$Id: packet.c,v 1.18.2.1 1998/06/26 18:20:44 mellon 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 */
+
+/* Compute the easy part of the checksum on a range of bytes. */
+
+u_int32_t checksum (buf, nbytes, sum)
+ unsigned char *buf;
+ int nbytes;
+ u_int32_t sum;
+{
+ int i;
+
+#ifdef DEBUG_CHECKSUM
+ debug ("checksum (%x %d %x)", buf, nbytes, sum);
+#endif
+
+ /* Checksum all the pairs of bytes first... */
+ for (i = 0; i < (nbytes & ~1); i += 2) {
+#ifdef DEBUG_CHECKSUM_VERBOSE
+ debug ("sum = %x", sum);
+#endif
+ sum += (u_int16_t) ntohs(*((u_int16_t *)(buf + i)));
+ }
+
+ /* If there's a single byte left over, checksum it, too. Network
+ byte order is big-endian, so the remaining byte is the high byte. */
+ if (i < nbytes) {
+#ifdef DEBUG_CHECKSUM_VERBOSE
+ debug ("sum = %x", sum);
+#endif
+ sum += buf [i] << 8;
+ }
+
+ return sum;
+}
+
+/* Fold the upper sixteen bits of the checksum down into the lower bits,
+ complement the sum, and then put it into network byte order. */
+
+u_int32_t wrapsum (sum)
+ u_int32_t sum;
+{
+#ifdef DEBUG_CHECKSUM
+ debug ("wrapsum (%x)", sum);
+#endif
+
+ while (sum > 0x10000) {
+ sum = (sum >> 16) + (sum & 0xFFFF);
+#ifdef DEBUG_CHECKSUM_VERBOSE
+ debug ("sum = %x", sum);
+#endif
+ sum += (sum >> 16);
+#ifdef DEBUG_CHECKSUM_VERBOSE
+ debug ("sum = %x", sum);
+#endif
+ }
+ sum = sum ^ 0xFFFF;
+#ifdef DEBUG_CHECKSUM_VERBOSE
+ debug ("sum = %x", sum);
+#endif
+
+#ifdef DEBUG_CHECKSUM
+ debug ("wrapsum returns %x", htons (sum));
+#endif
+ return htons(sum);
+}
+
+#ifdef PACKET_ASSEMBLY
+/* Assemble an hardware header... */
+/* XXX currently only supports ethernet; doesn't check for other types. */
+
+void assemble_hw_header (interface, buf, bufix, to)
+ struct interface_info *interface;
+ unsigned char *buf;
+ 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));
+ 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
+
+ memcpy (&buf [*bufix], &eh, sizeof eh);
+ *bufix += sizeof eh;
+}
+
+/* UDP header and IP header assembled together for convenience. */
+
+void assemble_udp_ip_header (interface, buf, bufix,
+ from, to, port, data, len)
+ struct interface_info *interface;
+ unsigned char *buf;
+ int *bufix;
+ u_int32_t from;
+ u_int32_t to;
+ unsigned int port;
+ unsigned char *data;
+ int len;
+{
+ struct ip ip;
+ struct udphdr udp;
+
+ /* Fill out the IP header */
+ ip.ip_v = 4;
+ ip.ip_hl = 5;
+ ip.ip_tos = IPTOS_LOWDELAY;
+ ip.ip_len = htons(sizeof(ip) + sizeof(udp) + len);
+ ip.ip_id = 0;
+ ip.ip_off = 0;
+ ip.ip_ttl = 16;
+ ip.ip_p = IPPROTO_UDP;
+ ip.ip_sum = 0;
+ ip.ip_src.s_addr = from;
+ ip.ip_dst.s_addr = to;
+
+ /* Checksum the IP header... */
+ ip.ip_sum = wrapsum (checksum ((unsigned char *)&ip, sizeof ip, 0));
+
+ /* Copy the ip header into the buffer... */
+ memcpy (&buf [*bufix], &ip, sizeof ip);
+ *bufix += sizeof ip;
+
+ /* Fill out the UDP header */
+ udp.uh_sport = local_port; /* XXX */
+ udp.uh_dport = port; /* XXX */
+ udp.uh_ulen = htons(sizeof(udp) + len);
+ memset (&udp.uh_sum, 0, sizeof udp.uh_sum);
+
+ /* Compute UDP checksums, including the ``pseudo-header'', the UDP
+ header and the data. */
+
+#if 0
+ udp.uh_sum =
+ wrapsum (checksum ((unsigned char *)&udp, sizeof udp,
+ checksum (data, len,
+ checksum ((unsigned char *)
+ &ip.ip_src,
+ sizeof ip.ip_src,
+ 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;
+ unsigned char *buf;
+ 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;
+#endif
+ memcpy (from -> haddr, eh.ether_shost, sizeof (eh.ether_shost));
+ from -> htype = ARPHRD_ETHER;
+ from -> hlen = sizeof eh.ether_shost;
+
+ return sizeof eh;
+}
+
+/* UDP header and IP header decoded together for convenience. */
+
+ssize_t decode_udp_ip_header (interface, buf, bufix, from, data, len)
+ struct interface_info *interface;
+ unsigned char *buf;
+ int bufix;
+ struct sockaddr_in *from;
+ unsigned char *data;
+ int len;
+{
+ struct ip *ip;
+ struct udphdr *udp;
+ u_int32_t ip_len = (buf [bufix] & 0xf) << 2;
+ u_int32_t sum, usum;
+
+ 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. */
+ if (wrapsum (checksum (buf + bufix, ip_len, 0))) {
+ note ("Bad IP checksum: %x",
+ wrapsum (checksum (buf + bufix, sizeof *ip, 0)));
+ return -1;
+ }
+
+ /* Copy out the IP source address... */
+ memcpy (&from -> sin_addr, &ip -> ip_src, 4);
+
+ /* Compute UDP checksums, including the ``pseudo-header'', the UDP
+ header and the data. If the UDP checksum field is zero, we're
+ not supposed to do a checksum. */
+
+ if (!data) {
+ data = buf + bufix + ip_len + sizeof *udp;
+ len -= ip_len + sizeof *udp;
+ }
+
+#if 0
+ usum = udp -> uh_sum;
+ udp -> uh_sum = 0;
+
+ sum = wrapsum (checksum ((unsigned char *)udp, sizeof *udp,
+ checksum (data, len,
+ checksum ((unsigned char *)
+ &ip -> ip_src,
+ sizeof ip -> ip_src,
+ IPPROTO_UDP +
+ (u_int32_t)
+ ntohs (udp -> uh_ulen)))));
+
+ if (usum && usum != sum) {
+ note ("Bad udp checksum: %x %x", usum, sum);
+ 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 */