[PATCH] ethhdr: add new member into pkt_hdr struct

[Nikola Pajkovsky]

before patch, when you want to access struct ethhdr you have to define
a new struct ethhdr and cast pkt->pkt_buf to struct ethhdr, which is
pretty annoying. Now ethhdr is in pkt_hdr struct and it's casted right
away ARPHDR_ETHER/ARPHDR_LOOP packet arrives.

Signed-off-by: Nikola Pajkovsky <npajkovs(a)redhat.com&gt;
---
 src/hostmon.c |    8 ++------
 src/othptab.c |    6 ++----
 src/packet.c  |    1 +
 src/packet.h  |   16 ++++++++++++----
 4 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/src/hostmon.c b/src/hostmon.c
index feeb629..c4c8fb1 100644
--- a/src/hostmon.c
+++ b/src/hostmon.c
@@ -980,12 +980,8 @@ void hostmon(const struct OPTIONS *options, time_t facilitytime, char
*ifptr,
 		/* get HW addresses */
 		switch (pkt.pkt_hatype) {
 		case ARPHRD_ETHER: {
-			struct ethhdr *hdr_eth =
-				(struct ethhdr *)pkt.pkt_buf;
-			memcpy(scratch_saddr, hdr_eth->h_source,
-			       ETH_ALEN);
-			memcpy(scratch_daddr, hdr_eth->h_dest,
-			       ETH_ALEN);
+			memcpy(scratch_saddr, pkt.ethhdr->h_source, ETH_ALEN);
+			memcpy(scratch_daddr, pkt.ethhdr->h_dest, ETH_ALEN);
 			list = elist;
 			break; }
 		case ARPHRD_FDDI: {
diff --git a/src/othptab.c b/src/othptab.c
index 62ce73f..831a907 100644
--- a/src/othptab.c
+++ b/src/othptab.c
@@ -183,10 +183,8 @@ struct othptabent *add_othp_entry(struct othptable *table, struct
pkt_hdr *pkt,
 
 	if ((table->mac) || (!is_ip)) {
 		if (pkt->pkt_hatype == ARPHRD_ETHER) {
-			convmacaddr((char *) (((struct ethhdr *) packet)->
-					      h_source), new_entry->smacaddr);
-			convmacaddr((char *) (((struct ethhdr *) packet)->
-					      h_dest), new_entry->dmacaddr);
+			convmacaddr((char *) pkt->ethhdr->h_source, new_entry->smacaddr);
+			convmacaddr((char *) pkt->ethhdr->h_dest, new_entry->dmacaddr);
 		} else if (pkt->pkt_hatype == ARPHRD_FDDI) {
 			convmacaddr((char *) (((struct fddihdr *) packet)->
 					      saddr), new_entry->smacaddr);
diff --git a/src/packet.c b/src/packet.c
index 20f20bf..b01c0ac 100644
--- a/src/packet.c
+++ b/src/packet.c
@@ -46,6 +46,7 @@ static int packet_adjust(struct pkt_hdr *pkt)
 	switch (pkt->pkt_hatype) {
 	case ARPHRD_ETHER:
 	case ARPHRD_LOOPBACK:
+		cast_hdr(ethhdr, pkt);
 		pkt->pkt_payload = pkt->pkt_buf;
 		pkt->pkt_payload += ETH_HLEN;
 		pkt->pkt_len -= ETH_HLEN;
diff --git a/src/packet.h b/src/packet.h
index 0bed4a0..561f74e 100644
--- a/src/packet.h
+++ b/src/packet.h
@@ -33,13 +33,21 @@ struct pkt_hdr {
 	unsigned char	pkt_pkttype;	/* Packet type: PACKET_OUTGOING, PACKET_BROADCAST, ... */
 	unsigned char	pkt_halen;	/* Length of address */
 	unsigned char	pkt_addr[8];	/* Physical layer address */
+	struct ethhdr  *ethhdr;
 	char		pkt_buf[MAX_PACKET_SIZE];
 };
 
-#define PACKET_INIT(packet) \
-	struct pkt_hdr packet = { \
-		.pkt_bufsize = MAX_PACKET_SIZE, \
-		.pkt_payload = NULL \
+#define pkt_cast_hdr(hdr, pkt)				\
+	do {						\
+		pkt.hdr = (struct hdr *) pkt.pkt_buf;	\
+	} while (0)
+
+
+#define PACKET_INIT(packet)					\
+	struct pkt_hdr packet = {				\
+		.pkt_bufsize = MAX_PACKET_SIZE,			\
+		.pkt_payload = NULL,				\
+		.ethhdr      = NULL,				\
 	};
 
 void open_socket(int *fd);
-- 
1.7.10.2