Normally I hate massive code drops, but heh.

The code has been drastically re-arranged.
Instead of populating a custom structure while parsing dhcp messages, we now pluck what we need right out of the message itself. We have custom functions and a lookup table to make this really easy.
This makes us more like dhclient and udhcpc, and will enable us to easily add (and remove!) more dhcp options without having to actually change the code (much).
We now store the real dhcp message we got in /var/db/dhcpcd-$iface.lease, the mtime of the file being used as when we got the lease. This file is read in when re-using an old lease instead of parsing the .info file.
The benefit of all of this means that we're actually ~15k smaller when compiled with the same features.
This has been tested for quite some time, and I'm pretty sure most bugs with the 3.2 branch have been fixed whilst making this. Right now, we are 99% command line compatible with the 3.2 branch.

1 files changed, 41 insertions, 59 deletions

diff --git a/bpf.c b/bpf.c
index 0266b696..341455e8 100644
--- a/bpf.c
+++ b/bpf.c
@@ -26,15 +26,11 @@
 
 #include <sys/types.h>
 #include <sys/ioctl.h>
-#include <sys/param.h>
 #include <sys/socket.h>
 #include <sys/uio.h>
 
 #include <net/bpf.h>
 #include <net/if.h>
-#include <netinet/in_systm.h>
-#include <netinet/in.h>
-#include <netinet/udp.h>
 #include <arpa/inet.h>
 
 #include <errno.h>
@@ -42,13 +38,13 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
 #include <unistd.h>
 
 #include "config.h"
+#include "common.h"
 #include "dhcp.h"
-#include "if.h"
-#include "socket.h"
+#include "logger.h"
+#include "net.h"
 #include "bpf-filter.h"
 
 int
@@ -60,6 +56,7 @@ open_socket(struct interface *iface, int protocol)
 	int flags;
 	struct ifreq ifr;
 	int buf = 0;
+	struct bpf_version pv;
 	struct bpf_program pf;
 
 	device = xmalloc(sizeof(char) * PATH_MAX);
@@ -72,26 +69,27 @@ open_socket(struct interface *iface, int protocol)
 	if (fd == -1)
 		return -1;
 
-	close_on_exec(fd);
+	if (ioctl(fd, BIOCVERSION, &pv) == -1)
+		goto eexit;
+	if (pv.bv_major != BPF_MAJOR_VERSION ||
+	    pv.bv_minor < BPF_MINOR_VERSION) {
+		logger(LOG_ERR, "BPF version mismatch - recompile " PACKAGE);
+		goto eexit;
+	}
+
 	memset(&ifr, 0, sizeof(ifr));
 	strlcpy(ifr.ifr_name, iface->name, sizeof(ifr.ifr_name));
-	if (ioctl(fd, BIOCSETIF, &ifr) == -1) {
-		close(fd);
-		return -1;
-	}
+	if (ioctl(fd, BIOCSETIF, &ifr) == -1)
+		goto eexit;
 
 	/* Get the required BPF buffer length from the kernel. */
-	if (ioctl(fd, BIOCGBLEN, &buf) == -1) {
-		close(fd);
-		return -1;
-	}
+	if (ioctl(fd, BIOCGBLEN, &buf) == -1)
+		goto eexit;
 	iface->buffer_length = buf;
 
 	flags = 1;
-	if (ioctl(fd, BIOCIMMEDIATE, &flags) == -1) {
-		close(fd);
-		return -1;
-	}
+	if (ioctl(fd, BIOCIMMEDIATE, &flags) == -1)
+		goto eexit;
 
 	/* Install the DHCP filter */
 	if (protocol == ETHERTYPE_ARP) {
@@ -101,16 +99,20 @@ open_socket(struct interface *iface, int protocol)
 		pf.bf_insns = dhcp_bpf_filter;
 		pf.bf_len = sizeof(dhcp_bpf_filter)/sizeof(dhcp_bpf_filter[0]);
 	}
-	if (ioctl(fd, BIOCSETF, &pf) == -1) {
-		close(fd);
-		return -1;
-	}
+	if (ioctl(fd, BIOCSETF, &pf) == -1)
+		goto eexit;
 
 	if (iface->fd > -1)
 		close(iface->fd);
+
+	close_on_exec(fd);
 	iface->fd = fd;
 
 	return fd;
+
+eexit:
+	close(fd);
+	return -1;
 }
 
 ssize_t
@@ -147,15 +149,10 @@ get_packet(const struct interface *iface, unsigned char *data,
 		unsigned char *buffer;
 		struct ether_header *hw;
 	} hdr;
-	union
-	{
-		unsigned char *buffer;
-		struct udp_dhcp_packet *packet;
-	} pay;
 	struct timespec ts;
 	ssize_t len;
 	unsigned char *payload;
-	bool have_data;
+	const uint8_t *d;
 
 	bpf.buffer = buffer;
 
@@ -172,15 +169,14 @@ get_packet(const struct interface *iface, unsigned char *data,
 	} else
 		bpf.buffer += *buffer_pos;
 
-	do {
-		len = 0;
-		have_data = false;
-
-		/* Ensure that the entire packet is in our buffer */
-		if (*buffer_pos +
-		    bpf.packet->bh_hdrlen +
-		    bpf.packet->bh_caplen > (unsigned)*buffer_len)
-			break;
+	for (; bpf.buffer - buffer < *buffer_len; 
+		bpf.buffer += BPF_WORDALIGN(bpf.packet->bh_hdrlen +
+					    bpf.packet->bh_caplen),
+		*buffer_pos = bpf.buffer - buffer)
+	{
+		/* Ensure we have the whole packet */
+		if (bpf.packet->bh_caplen != bpf.packet->bh_datalen)
+			continue;
 
 		hdr.buffer = bpf.buffer + bpf.packet->bh_hdrlen;
 		payload = hdr.buffer + sizeof(*hdr.hw);
@@ -189,29 +185,15 @@ get_packet(const struct interface *iface, unsigned char *data,
 		if (hdr.hw->ether_type == htons (ETHERTYPE_ARP)) {
 			len = bpf.packet->bh_caplen - sizeof(*hdr.hw);
 			memcpy(data, payload, len);
-			have_data = true;
+			return len;
 		} else {
-			if (valid_dhcp_packet(payload) >= 0) {
-				pay.buffer = payload;
-				len = ntohs(pay.packet->ip.ip_len) -
-					sizeof(pay.packet->ip) -
-					sizeof(pay.packet->udp);
-				memcpy(data, &pay.packet->dhcp, len);
-				have_data = true;
+			if (valid_udp_packet(payload) >= 0) {
+				len = get_udp_data(&d, payload);
+				memcpy(data, d, len);
+				return len;
 			}
 		}
-
-		/* Update the buffer_pos pointer */
-		bpf.buffer += BPF_WORDALIGN(bpf.packet->bh_hdrlen +
-					    bpf.packet->bh_caplen);
-		if (bpf.buffer - buffer < *buffer_len)
-			*buffer_pos = bpf.buffer - buffer;
-		else
-			*buffer_pos = 0;
-
-		if (have_data)
-			return len;
-	} while (*buffer_pos);
+	}
 
 	/* No valid packets left, so return */
 	*buffer_pos = 0;