Split interface and socket out into OS bpf, if-bsd and if-linux.

1 files changed, 347 insertions, 0 deletions

diff --git a/if-linux.c b/if-linux.c
new file mode 100644
index 00000000..0c3c1638
--- /dev/null
+++ b/if-linux.c
@@ -0,0 +1,347 @@
+/* 
+ * dhcpcd - DHCP client daemon
+ * Copyright 2006-2008 Roy Marples <roy@marples.name>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ */
+
+#include <asm/types.h> /* Needed for 2.4 kernels */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/param.h>
+
+#include <arpa/inet.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <netinet/ether.h>
+#include <netpacket/packet.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "config.h"
+#include "common.h"
+#include "dhcp.h"
+#include "if.h"
+#include "logger.h"
+
+/* This netlink stuff is overly compex IMO.
+ * The BSD implementation is much cleaner and a lot less code.
+ * send_netlink handles the actual transmission so we can work out
+ * if there was an error or not. */
+#define BUFFERLEN 256
+static int
+send_netlink(struct nlmsghdr *hdr)
+{
+	int s;
+	pid_t mypid = getpid ();
+	struct sockaddr_nl nl;
+	struct iovec iov;
+	struct msghdr msg;
+	static unsigned int seq;
+	char *buffer;
+	ssize_t bytes;
+	union
+	{
+		char *buffer;
+		struct nlmsghdr *nlm;
+	} h;
+	int len, l;
+	struct nlmsgerr *err;
+
+	if ((s = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) == -1) {
+		logger(LOG_ERR, "socket: %s", strerror(errno));
+		return -1;
+	}
+
+	memset(&nl, 0, sizeof(nl));
+	nl.nl_family = AF_NETLINK;
+	if (bind(s, (struct sockaddr *)&nl, sizeof(nl)) == -1) {
+		logger(LOG_ERR, "bind: %s", strerror(errno));
+		close(s);
+		return -1;
+	}
+
+	memset(&iov, 0, sizeof(iov));
+	iov.iov_base = hdr;
+	iov.iov_len = hdr->nlmsg_len;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.msg_name = &nl;
+	msg.msg_namelen = sizeof(nl);
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+
+	/* Request a reply */
+	hdr->nlmsg_flags |= NLM_F_ACK;
+	hdr->nlmsg_seq = ++seq;
+
+	if (sendmsg(s, &msg, 0) == -1) {
+		logger(LOG_ERR, "write: %s", strerror(errno));
+		close(s);
+		return -1;
+	}
+
+	buffer = xzalloc(sizeof(char) * BUFFERLEN);
+	iov.iov_base = buffer;
+
+	for (;;) {
+		iov.iov_len = BUFFERLEN;
+		bytes = recvmsg(s, &msg, 0);
+
+		if (bytes == -1) {
+			if (errno != EINTR)
+				logger (LOG_ERR, "recvmsg: %s",
+					strerror(errno));
+			continue;
+		}
+
+		if (bytes == 0) {
+			logger(LOG_ERR, "netlink: EOF");
+			goto eexit;
+		}
+
+		if (msg.msg_namelen != sizeof(nl)) {
+			logger(LOG_ERR,
+			       "netlink: sender address length mismatch");
+			goto eexit;
+		}
+
+		for (h.buffer = buffer; bytes >= (signed) sizeof(*h.nlm); ) {
+			len = h.nlm->nlmsg_len;
+			l = len - sizeof(*h.nlm);
+			err = (struct nlmsgerr *)NLMSG_DATA(h.nlm);
+
+			if (l < 0 || len > bytes) {
+				if (msg.msg_flags & MSG_TRUNC)
+					logger(LOG_ERR,
+					       "netlink: truncated message");
+				else
+					logger(LOG_ERR,
+					       "netlink: malformed message");
+				goto eexit;
+			}
+
+			/* Ensure it's our message */
+			if (nl.nl_pid != 0 ||
+			    (pid_t)h.nlm->nlmsg_pid != mypid ||
+			    h.nlm->nlmsg_seq != seq)
+			{
+				/* Next Message */
+				bytes -= NLMSG_ALIGN(len);
+				h.buffer += NLMSG_ALIGN(len);
+				continue;
+			}
+
+			/* We get an NLMSG_ERROR back with a code of zero for success */
+			if (h.nlm->nlmsg_type != NLMSG_ERROR) {
+				logger(LOG_ERR, "netlink: unexpected reply %d",
+				       h.nlm->nlmsg_type);
+				goto eexit;
+			}
+
+			if ((unsigned)l < sizeof(*err)) {
+				logger(LOG_ERR, "netlink: error truncated");
+				goto eexit;
+			}
+
+			if (err->error == 0) {
+				close(s);
+				free(buffer);
+				return l;
+			}
+
+			errno = -err->error;
+			/* Don't report on something already existing */
+			if (errno != EEXIST)
+				logger(LOG_ERR, "netlink: %s", strerror(errno));
+			goto eexit;
+		}
+	}
+
+eexit:
+	close(s);
+	free(buffer);
+	return -1;
+}
+
+#define NLMSG_TAIL(nmsg) \
+	((struct rtattr *)(((ptrdiff_t)(nmsg))+NLMSG_ALIGN((nmsg)->nlmsg_len)))
+
+static int
+add_attr_l(struct nlmsghdr *n, unsigned int maxlen, int type,
+	   const void *data, int alen)
+{
+	int len = RTA_LENGTH(alen);
+	struct rtattr *rta;
+
+	if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen) {
+		logger(LOG_ERR, "add_attr_l: message exceeded bound of %d\n",
+		       maxlen);
+		return -1;
+	}
+
+	rta = NLMSG_TAIL(n);
+	rta->rta_type = type;
+	rta->rta_len = len;
+	memcpy(RTA_DATA(rta), data, alen);
+	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);
+
+	return 0;
+}
+
+static int
+add_attr_32(struct nlmsghdr *n, unsigned int maxlen, int type, uint32_t data)
+{
+	int len = RTA_LENGTH(sizeof(data));
+	struct rtattr *rta;
+
+	if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen) {
+		logger(LOG_ERR, "add_attr32: message exceeded bound of %d\n",
+		       maxlen);
+		return -1;
+	}
+
+	rta = NLMSG_TAIL(n);
+	rta->rta_type = type;
+	rta->rta_len = len;
+	memcpy(RTA_DATA(rta), &data, sizeof(data));
+	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
+
+	return 0;
+}
+
+struct nlma
+{
+	struct nlmsghdr hdr;
+	struct ifaddrmsg ifa; 
+	char buffer[64];
+};
+
+struct nlmr
+{
+	struct nlmsghdr hdr;
+	struct rtmsg rt;
+	char buffer[256];
+};
+
+int
+if_address(const char *ifname,
+	   struct in_addr address, struct in_addr netmask,
+	   struct in_addr broadcast, int del)
+{
+	struct nlma *nlm;
+	int retval;
+
+	nlm = xzalloc(sizeof(*nlm));
+	nlm->hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
+	nlm->hdr.nlmsg_flags = NLM_F_REQUEST;
+	if (!del)
+		nlm->hdr.nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
+	nlm->hdr.nlmsg_type = del ? RTM_DELADDR : RTM_NEWADDR;
+	if (!(nlm->ifa.ifa_index = if_nametoindex(ifname))) {
+		logger(LOG_ERR, "if_nametoindex: no index for interface `%s'",
+		       ifname);
+		free(nlm);
+		return -1;
+	}
+	nlm->ifa.ifa_family = AF_INET;
+	nlm->ifa.ifa_prefixlen = inet_ntocidr(netmask);
+	/* This creates the aliased interface */
+	add_attr_l(&nlm->hdr, sizeof(*nlm), IFA_LABEL,
+		   ifname, strlen(ifname) + 1);
+	add_attr_l(&nlm->hdr, sizeof(*nlm), IFA_LOCAL,
+		   &address.s_addr, sizeof(address.s_addr));
+	if (!del)
+		add_attr_l(&nlm->hdr, sizeof(*nlm), IFA_BROADCAST,
+			   &broadcast.s_addr, sizeof(broadcast.s_addr));
+
+	retval = send_netlink(&nlm->hdr);
+	free(nlm);
+	return retval;
+}
+
+int
+if_route(const char *ifname,
+	 struct in_addr destination, struct in_addr netmask,
+	 struct in_addr gateway, int metric, int change, int del)
+{
+	struct nlmr *nlm;
+	unsigned int ifindex;
+	int retval;
+
+	log_route(destination, netmask, gateway, metric, change, del);
+
+	if (!(ifindex = if_nametoindex(ifname))) {
+		logger(LOG_ERR, "if_nametoindex: no index for interface `%s'",
+		       ifname);
+		return -1;
+	}
+
+	nlm = xzalloc(sizeof(*nlm));
+	nlm->hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
+	if (change)
+		nlm->hdr.nlmsg_flags = NLM_F_REPLACE;
+	else if (!del)
+		nlm->hdr.nlmsg_flags = NLM_F_CREATE | NLM_F_EXCL;
+	nlm->hdr.nlmsg_flags |= NLM_F_REQUEST;
+	nlm->hdr.nlmsg_type = del ? RTM_DELROUTE : RTM_NEWROUTE;
+	nlm->rt.rtm_family = AF_INET;
+	nlm->rt.rtm_table = RT_TABLE_MAIN;
+
+	if (del)
+		nlm->rt.rtm_scope = RT_SCOPE_NOWHERE;
+	else {
+		nlm->hdr.nlmsg_flags |= NLM_F_CREATE | NLM_F_EXCL;
+		nlm->rt.rtm_protocol = RTPROT_BOOT;
+		if (netmask.s_addr == INADDR_BROADCAST ||
+		    gateway.s_addr == INADDR_ANY)
+			nlm->rt.rtm_scope = RT_SCOPE_LINK;
+		else
+			nlm->rt.rtm_scope = RT_SCOPE_UNIVERSE;
+		nlm->rt.rtm_type = RTN_UNICAST;
+	}
+
+	nlm->rt.rtm_dst_len = inet_ntocidr(netmask);
+	add_attr_l(&nlm->hdr, sizeof(*nlm), RTA_DST,
+		   &destination.s_addr, sizeof(destination.s_addr));
+	if (netmask.s_addr != INADDR_BROADCAST &&
+	    destination.s_addr != gateway.s_addr)
+		add_attr_l(&nlm->hdr, sizeof(*nlm), RTA_GATEWAY,
+			   &gateway.s_addr, sizeof(gateway.s_addr));
+
+	add_attr_32(&nlm->hdr, sizeof(*nlm), RTA_OIF, ifindex);
+	add_attr_32(&nlm->hdr, sizeof(*nlm), RTA_PRIORITY, metric);
+
+	retval = send_netlink(&nlm->hdr);
+	free(nlm);
+	return retval;
+}