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authorPhilip Paeps <philip@FreeBSD.org>2009-10-23 14:43:17 +0000
committerPhilip Paeps <philip@FreeBSD.org>2009-10-23 14:43:17 +0000
commit1ca0e46fdfb82b931d25332101e5d56289794911 (patch)
treed283f9cb1fc13d3a0c23f2d3c1098420badddcc2
parentde411f4cd2b28c94938e2548d6a28ec8785856f1 (diff)
downloadsrc-1ca0e46fdfb82b931d25332101e5d56289794911.tar.gz
src-1ca0e46fdfb82b931d25332101e5d56289794911.zip
MFC r198352
Make dhclient use bootpc (68) as the source port for unicast DHCPREQUEST packets instead of allowing the protocol stack to pick a random source port. This fixes the behaviour where dhclient would never transition from RENEWING to BOUND without going through REBINDING in networks which are paranoid about DHCP spoofing, such as most mainstream cable-broadband ISP networks. Obtained from: OpenBSD Reviewed by: brooks Approved by: re (kib)
Notes
Notes: svn path=/stable/8/; revision=198405
-rw-r--r--sbin/dhclient/bpf.c45
-rw-r--r--sbin/dhclient/dhcpd.h3
-rw-r--r--sbin/dhclient/packet.c11
3 files changed, 41 insertions, 18 deletions
diff --git a/sbin/dhclient/bpf.c b/sbin/dhclient/bpf.c
index 8a669e1befb3..9f8e45fbfd21 100644
--- a/sbin/dhclient/bpf.c
+++ b/sbin/dhclient/bpf.c
@@ -90,11 +90,23 @@ if_register_bpf(struct interface_info *info)
void
if_register_send(struct interface_info *info)
{
+ int sock, on = 1;
+
/*
* If we're using the bpf API for sending and receiving, we
* don't need to register this interface twice.
*/
info->wfdesc = info->rfdesc;
+
+ /*
+ * Use raw socket for unicast send.
+ */
+ if ((sock = socket(AF_INET, SOCK_RAW, IPPROTO_UDP)) == -1)
+ error("socket(SOCK_RAW): %m");
+ if (setsockopt(sock, IPPROTO_IP, IP_HDRINCL, &on,
+ sizeof(on)) == -1)
+ error("setsockopt(IP_HDRINCL): %m");
+ info->ufdesc = sock;
}
/*
@@ -244,35 +256,32 @@ send_packet(struct interface_info *interface, struct dhcp_packet *raw,
{
unsigned char buf[256];
struct iovec iov[2];
+ struct msghdr msg;
int result, bufp = 0;
- int sock;
-
- if (to->sin_addr.s_addr != INADDR_BROADCAST) {
- note("SENDING DIRECT");
- /* We know who the server is, send the packet via
- normal socket interface */
-
- if ((sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) >= 0) {
- result = sendto (sock, (char *)raw, len, 0,
- (struct sockaddr *)to, sizeof *to);
- close(sock);
- if (result > 0)
- return result;
- }
- }
/* Assemble the headers... */
- assemble_hw_header(interface, buf, &bufp, hto);
+ if (to->sin_addr.s_addr == INADDR_BROADCAST)
+ assemble_hw_header(interface, buf, &bufp, hto);
assemble_udp_ip_header(buf, &bufp, from.s_addr,
to->sin_addr.s_addr, to->sin_port, (unsigned char *)raw, len);
- /* Fire it off */
iov[0].iov_base = (char *)buf;
iov[0].iov_len = bufp;
iov[1].iov_base = (char *)raw;
iov[1].iov_len = len;
- result = writev(interface->wfdesc, iov, 2);
+ /* Fire it off */
+ if (to->sin_addr.s_addr == INADDR_BROADCAST)
+ result = writev(interface->wfdesc, iov, 2);
+ else {
+ memset(&msg, 0, sizeof(msg));
+ msg.msg_name = (struct sockaddr *)to;
+ msg.msg_namelen = sizeof(*to);
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 2;
+ result = sendmsg(interface->ufdesc, &msg, 0);
+ }
+
if (result < 0)
warning("send_packet: %m");
return (result);
diff --git a/sbin/dhclient/dhcpd.h b/sbin/dhclient/dhcpd.h
index 8097f14b1de1..bd4c9c0b5e15 100644
--- a/sbin/dhclient/dhcpd.h
+++ b/sbin/dhclient/dhcpd.h
@@ -37,6 +37,8 @@
* 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''.
+ *
+ * $FreeBSD$
*/
#include <sys/types.h>
@@ -194,6 +196,7 @@ struct interface_info {
char name[IFNAMSIZ];
int rfdesc;
int wfdesc;
+ int ufdesc;
unsigned char *rbuf;
size_t rbuf_max;
size_t rbuf_offset;
diff --git a/sbin/dhclient/packet.c b/sbin/dhclient/packet.c
index 484953ca2d98..2e90cc85a8de 100644
--- a/sbin/dhclient/packet.c
+++ b/sbin/dhclient/packet.c
@@ -135,6 +135,17 @@ assemble_udp_ip_header(unsigned char *buf, int *bufix, u_int32_t from,
ip.ip_dst.s_addr = to;
ip.ip_sum = wrapsum(checksum((unsigned char *)&ip, sizeof(ip), 0));
+
+ /*
+ * While the BPF -- used for broadcasts -- expects a "true" IP header
+ * with all the bytes in network byte order, the raw socket interface
+ * which is used for unicasts expects the ip_len field to be in host
+ * byte order. In both cases, the checksum has to be correct, so this
+ * is as good a place as any to turn the bytes around again.
+ */
+ if (to != INADDR_BROADCAST)
+ ip.ip_len = ntohs(ip.ip_len);
+
memcpy(&buf[*bufix], &ip, sizeof(ip));
*bufix += sizeof(ip);