Re-write the client state engine around a simple timer instead of complex loops. Use the re-transmission times as per RFC 2131. Integrate the ARP handling code in the new engine so we are able to defend our IPV4LL address whilst negotiating a DHCP lease. This also means we're able to bind the address and fork BEFORE waiting to send announcements which makes us appear faster on the commandline.

1 files changed, 34 insertions, 31 deletions

diff --git a/lpf.c b/lpf.c
index 87e6460a..c507378f 100644
--- a/lpf.c
+++ b/lpf.c
@@ -57,9 +57,6 @@
 #include "net.h"
 #include "bpf-filter.h"
 
-/* A suitably large buffer for all transactions. */
-#define BUFFER_LENGTH 4096
-
 /* Broadcast address for IPoIB */
 static const uint8_t ipv4_bcast_addr[] = {
 	0x00, 0xff, 0xff, 0xff,
@@ -79,6 +76,7 @@ open_socket(struct interface *iface, int protocol)
 	} su;
 	struct sock_fprog pf;
 	int flags;
+	int *fd;
 
 	if ((s = socket(PF_PACKET, SOCK_DGRAM, htons(protocol))) == -1)
 		return -1;
@@ -92,10 +90,13 @@ open_socket(struct interface *iface, int protocol)
 	}
 	/* Install the DHCP filter */
 	memset(&pf, 0, sizeof(pf));
+#ifdef ENABLE_ARP
 	if (protocol == ETHERTYPE_ARP) {
 		pf.filter = UNCONST(arp_bpf_filter);
 		pf.len = arp_bpf_filter_len;
-	} else {
+	} else
+#endif
+	{
 		pf.filter = UNCONST(dhcp_bpf_filter);
 		pf.len = dhcp_bpf_filter_len;
 	}
@@ -108,15 +109,15 @@ open_socket(struct interface *iface, int protocol)
 		goto eexit;
 	if (close_on_exec(s) == -1)
 		goto eexit;
-	if (iface->fd > -1)
-		close(iface->fd);
-	iface->fd = s;
-	iface->socket_protocol = protocol;
-	if (iface->buffer == NULL) {
-		iface->buffer_size = BUFFER_LENGTH;
-		iface->buffer = xmalloc(iface->buffer_size);
-		iface->buffer_len = iface->buffer_pos = 0;
-	}
+#ifdef ENABLE_ARP
+	if (protocol == ETHERTYPE_ARP)
+		fd = &iface->arp_fd;
+	else
+#endif
+		fd = &iface->fd;
+	if (*fd != -1)
+		close(*fd);
+	*fd = s;
 	return s;
 
 eexit:
@@ -125,7 +126,7 @@ eexit:
 }
 
 ssize_t
-send_raw_packet(const struct interface *iface, int type,
+send_raw_packet(const struct interface *iface, int protocol,
 		const void *data, ssize_t len)
 {
 	union sockunion {
@@ -133,10 +134,11 @@ send_raw_packet(const struct interface *iface, int type,
 		struct sockaddr_ll sll;
 		struct sockaddr_storage ss;
 	} su;
+	int fd;
 
 	memset(&su, 0, sizeof(su));
 	su.sll.sll_family = AF_PACKET;
-	su.sll.sll_protocol = htons(type);
+	su.sll.sll_protocol = htons(protocol);
 	if (!(su.sll.sll_ifindex = if_nametoindex(iface->name))) {
 		errno = ENOENT;
 		return -1;
@@ -148,30 +150,31 @@ send_raw_packet(const struct interface *iface, int type,
 		       &ipv4_bcast_addr, sizeof(ipv4_bcast_addr));
 	else
 		memset(&su.sll.sll_addr, 0xff, iface->hwlen);
+#ifdef ENABLE_ARP
+	if (protocol == ETHERTYPE_ARP)
+		fd = iface->arp_fd;
+	else
+#endif
+		fd = iface->fd;
 
-	return sendto(iface->fd, data, len, 0, &su.sa, sizeof(su));
+	return sendto(fd, data, len, 0, &su.sa, sizeof(su));
 }
 
 ssize_t
-get_packet(struct interface *iface, void *data, ssize_t len)
+get_raw_packet(struct interface *iface, _unused int protocol,
+	       void *data, ssize_t len)
 {
 	ssize_t bytes;
-	const uint8_t *p;
+	int fd;
 
-	bytes = read(iface->fd, iface->buffer, iface->buffer_size);
+#ifdef ENABLE_ARP
+	if (protocol == ETHERTYPE_ARP)
+		fd = iface->arp_fd;
+	else
+#endif
+		fd = iface->fd;
+	bytes = read(fd, data, len);
 	if (bytes == -1)
 		return errno == EAGAIN ? 0 : -1;
-
-	/* If it's an ARP reply, then just send it back */
-	if (iface->socket_protocol == ETHERTYPE_ARP) {
-		p = iface->buffer;
-	} else {
-		if (valid_udp_packet(iface->buffer) != 0)
-			return -1;
-		bytes = get_udp_data(&p, iface->buffer);
-	}
-	if (bytes > len)
-		bytes = len;
-	memcpy(data, p, bytes);
 	return bytes;
 }