net: Refactor bootp packet length computations

Eliminate pointer subtraction that recovers values computed earlier

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Simon Glass <sjg@chromium.org>

diff --git a/net/bootp.c b/net/bootp.c
index 7346993..84ac8a0 100644 (file)
--- a/net/bootp.c
+++ b/net/bootp.c
@@ -581,7 +581,8 @@ BootpRequest(void)
 {
        uchar *pkt, *iphdr;
        struct Bootp_t *bp;
-       int ext_len, pktlen, iplen;
+       int extlen, pktlen, iplen;
+       int eth_hdr_size;
 #ifdef CONFIG_BOOTP_RANDOM_DELAY
        ulong i, rand_ms;
 #endif
@@ -610,7 +611,8 @@ BootpRequest(void)
        pkt = NetTxPacket;
        memset((void *)pkt, 0, PKTSIZE);
 
-       pkt += NetSetEther(pkt, NetBcastAddr, PROT_IP);
+       eth_hdr_size = NetSetEther(pkt, NetBcastAddr, PROT_IP);
+       pkt += eth_hdr_size;
 
        /*
         * Next line results in incorrect packet size being transmitted,
@@ -639,9 +641,9 @@ BootpRequest(void)
 
        /* Request additional information from the BOOTP/DHCP server */
 #if defined(CONFIG_CMD_DHCP)
-       ext_len = DhcpExtended((u8 *)bp->bp_vend, DHCP_DISCOVER, 0, 0);
+       extlen = DhcpExtended((u8 *)bp->bp_vend, DHCP_DISCOVER, 0, 0);
 #else
-       ext_len = BootpExtended((u8 *)bp->bp_vend);
+       extlen = BootpExtended((u8 *)bp->bp_vend);
 #endif
 
        /*
@@ -660,9 +662,8 @@ BootpRequest(void)
         * Calculate proper packet lengths taking into account the
         * variable size of the options field
         */
-       pktlen = ((int)(pkt-NetTxPacket)) + BOOTP_HDR_SIZE -
-               sizeof(bp->bp_vend) + ext_len;
-       iplen = BOOTP_HDR_SIZE - sizeof(bp->bp_vend) + ext_len;
+       iplen = BOOTP_HDR_SIZE - OPT_FIELD_SIZE + extlen;
+       pktlen = eth_hdr_size + IP_UDP_HDR_SIZE + iplen;
        net_set_udp_header(iphdr, 0xFFFFFFFFL, PORT_BOOTPS, PORT_BOOTPC, iplen);
        NetSetTimeout(SELECT_TIMEOUT, BootpTimeout);
 
@@ -798,13 +799,15 @@ static void DhcpSendRequestPkt(struct Bootp_t *bp_offer)
        uchar *pkt, *iphdr;
        struct Bootp_t *bp;
        int pktlen, iplen, extlen;
+       int eth_hdr_size;
        IPaddr_t OfferedIP;
 
        debug("DhcpSendRequestPkt: Sending DHCPREQUEST\n");
        pkt = NetTxPacket;
        memset((void *)pkt, 0, PKTSIZE);
 
-       pkt += NetSetEther(pkt, NetBcastAddr, PROT_IP);
+       eth_hdr_size = NetSetEther(pkt, NetBcastAddr, PROT_IP);
+       pkt += eth_hdr_size;
 
        iphdr = pkt;    /* We'll need this later to set proper pkt size */
        pkt += IP_UDP_HDR_SIZE;
@@ -841,9 +844,8 @@ static void DhcpSendRequestPkt(struct Bootp_t *bp_offer)
        extlen = DhcpExtended((u8 *)bp->bp_vend, DHCP_REQUEST,
                NetDHCPServerIP, OfferedIP);
 
-       pktlen = ((int)(pkt-NetTxPacket)) + BOOTP_HDR_SIZE -
-               sizeof(bp->bp_vend) + extlen;
-       iplen = BOOTP_HDR_SIZE - sizeof(bp->bp_vend) + extlen;
+       iplen = BOOTP_HDR_SIZE - OPT_FIELD_SIZE + extlen;
+       pktlen = eth_hdr_size + IP_UDP_HDR_SIZE + iplen;
        net_set_udp_header(iphdr, 0xFFFFFFFFL, PORT_BOOTPS, PORT_BOOTPC, iplen);
 
        debug("Transmitting DHCPREQUEST packet: len = %d\n", pktlen);