DHCP: Fix in_cksum for big endian

diff --git a/src/dhcp.c b/src/dhcp.c
index 00763fe3ee178412e9fe2e6015fd55e01d024725..679e409a99aa08849878f8402c0e424f195c8b14 100644 (file)
--- a/src/dhcp.c
+++ b/src/dhcp.c
@@ -1584,7 +1584,7 @@ eexit:
 }
 
 static uint16_t
-in_cksum(void *data, size_t len, uint32_t *isum)
+in_cksum(const void *data, size_t len, uint32_t *isum)
 {
        const uint16_t *word = data;
        uint32_t sum = isum != NULL ? *isum : 0;
@@ -1593,7 +1593,7 @@ in_cksum(void *data, size_t len, uint32_t *isum)
                sum += *word++;
 
        if (len == 1)
-               sum += *(const uint8_t *)word;
+               sum += htons(*(const uint8_t *)word << 8);
 
        if (isum != NULL)
                *isum = sum;
@@ -3293,7 +3293,8 @@ valid_udp_packet(void *packet, size_t plen, struct in_addr *from,
        pseudo_ip.ip_len = udp->uh_ulen;
        csum = 0;
        in_cksum(&pseudo_ip, sizeof(pseudo_ip), &csum);
-       if (in_cksum(udp, ntohs(udp->uh_ulen), &csum) != uh_sum) {
+       csum = in_cksum(udp, ntohs(udp->uh_ulen), &csum);
+       if (csum != uh_sum) {
                errno = EINVAL;
                return -1;
        }