udhcpc: merge clientsocket.c into dhcpc.c. +4 bytes.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 3e2cd12..a03e25c 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -1,11 +1,22 @@
/* vi: set sw=4 ts=4: */
-/* dhcpc.c
- *
+/*
* udhcp DHCP client
*
* Russ Dill <Russ.Dill@asu.edu> July 2001
*
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <syslog.h>
/* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
@@ -15,6 +26,16 @@
#include "dhcpc.h"
#include "options.h"
+#include <asm/types.h>
+#if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined(_NEWLIB_VERSION)
+# include <netpacket/packet.h>
+# include <net/ethernet.h>
+#else
+# include <linux/if_packet.h>
+# include <linux/if_ether.h>
+#endif
+#include <linux/filter.h>
+
static int sockfd = -1;
@@ -42,6 +63,79 @@
/* struct client_config_t client_config is in bb_common_bufsiz1 */
+
+static int udhcp_raw_socket(int ifindex)
+{
+ int fd;
+ struct sockaddr_ll sock;
+
+ /*
+ * Comment:
+ *
+ * I've selected not to see LL header, so BPF doesn't see it, too.
+ * The filter may also pass non-IP and non-ARP packets, but we do
+ * a more complete check when receiving the message in userspace.
+ *
+ * and filter shamelessly stolen from:
+ *
+ * http://www.flamewarmaster.de/software/dhcpclient/
+ *
+ * There are a few other interesting ideas on that page (look under
+ * "Motivation"). Use of netlink events is most interesting. Think
+ * of various network servers listening for events and reconfiguring.
+ * That would obsolete sending HUP signals and/or make use of restarts.
+ *
+ * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
+ * License: GPL v2.
+ *
+ * TODO: make conditional?
+ */
+#define SERVER_AND_CLIENT_PORTS ((67 << 16) + 68)
+ static const struct sock_filter filter_instr[] = {
+ /* check for udp */
+ BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 2, 0), /* L5, L1, is UDP? */
+ /* ugly check for arp on ethernet-like and IPv4 */
+ BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 2), /* L1: */
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 0x08000604, 3, 4), /* L3, L4 */
+ /* skip IP header */
+ BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0), /* L5: */
+ /* check udp source and destination ports */
+ BPF_STMT(BPF_LD|BPF_W|BPF_IND, 0),
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, SERVER_AND_CLIENT_PORTS, 0, 1), /* L3, L4 */
+ /* returns */
+ BPF_STMT(BPF_RET|BPF_K, 0x0fffffff ), /* L3: pass */
+ BPF_STMT(BPF_RET|BPF_K, 0), /* L4: reject */
+ };
+ static const struct sock_fprog filter_prog = {
+ .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
+ /* casting const away: */
+ .filter = (struct sock_filter *) filter_instr,
+ };
+
+ log1("Opening raw socket on ifindex %d", ifindex); //log2?
+
+ fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
+ log1("Got raw socket fd %d", fd); //log2?
+
+ if (SERVER_PORT == 67 && CLIENT_PORT == 68) {
+ /* Use only if standard ports are in use */
+ /* Ignoring error (kernel may lack support for this) */
+ if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
+ sizeof(filter_prog)) >= 0)
+ log1("Attached filter to raw socket fd %d", fd); // log?
+ }
+
+ sock.sll_family = AF_PACKET;
+ sock.sll_protocol = htons(ETH_P_IP);
+ sock.sll_ifindex = ifindex;
+ xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
+ log1("Created raw socket");
+
+ return fd;
+}
+
+
/* just a little helper */
static void change_listen_mode(int new_mode)
{
@@ -60,7 +154,7 @@
sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
else if (new_mode != LISTEN_NONE)
sockfd = udhcp_raw_socket(client_config.ifindex);
- /* else LISTEN_NONE: sockfd stay closed */
+ /* else LISTEN_NONE: sockfd stays closed */
}