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--- a/networking/udhcp/packet.c
+++ b/networking/udhcp/packet.c
@@ -114,6 +114,10 @@ uint16_t FAST_FUNC udhcp_checksum(void *
return ~sum;
}
+int udhcp_get_payload_len(struct dhcpMessage *payload)
+{
+ return sizeof(struct dhcpMessage) - DHCP_OPTIONS_BUFSIZE + end_option(payload->options) + sizeof(payload->options[0]);
+}
/* Construct a ip/udp header for a packet, send packet */
int FAST_FUNC udhcp_send_raw_packet(struct dhcpMessage *payload,
@@ -126,11 +130,7 @@ int FAST_FUNC udhcp_send_raw_packet(stru
int fd;
int result = -1;
const char *msg;
-
- enum {
- IP_UPD_DHCP_SIZE = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
- UPD_DHCP_SIZE = IP_UPD_DHCP_SIZE - offsetof(struct udp_dhcp_packet, udp),
- };
+ int p_len = udhcp_get_payload_len(payload);
fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
if (fd < 0) {
@@ -140,7 +140,7 @@ int FAST_FUNC udhcp_send_raw_packet(stru
memset(&dest, 0, sizeof(dest));
memset(&packet, 0, sizeof(packet));
- packet.data = *payload; /* struct copy */
+ memcpy(&(packet.data), payload, p_len);
dest.sll_family = AF_PACKET;
dest.sll_protocol = htons(ETH_P_IP);
@@ -157,23 +157,18 @@ int FAST_FUNC udhcp_send_raw_packet(stru
packet.ip.daddr = dest_ip;
packet.udp.source = htons(source_port);
packet.udp.dest = htons(dest_port);
- /* size, excluding IP header: */
- packet.udp.len = htons(UPD_DHCP_SIZE);
- /* for UDP checksumming, ip.len is set to UDP packet len */
+ p_len += sizeof(packet.udp);
+ packet.udp.len = htons(p_len);
packet.ip.tot_len = packet.udp.len;
- packet.udp.check = udhcp_checksum(&packet, IP_UPD_DHCP_SIZE);
- /* but for sending, it is set to IP packet len */
- packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE);
+ p_len += sizeof(packet.ip);
+ packet.udp.check = udhcp_checksum(&packet, p_len);
+ packet.ip.tot_len = htons(p_len);
packet.ip.ihl = sizeof(packet.ip) >> 2;
packet.ip.version = IPVERSION;
packet.ip.ttl = IPDEFTTL;
packet.ip.check = udhcp_checksum(&packet.ip, sizeof(packet.ip));
- /* Currently we send full-sized DHCP packets (zero padded).
- * If you need to change this: last byte of the packet is
- * packet.data.options[end_option(packet.data.options)]
- */
- result = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0,
+ result = sendto(fd, &packet, p_len, 0,
(struct sockaddr *) &dest, sizeof(dest));
msg = "sendto";
ret_close:
@@ -225,8 +220,7 @@ int FAST_FUNC udhcp_send_kernel_packet(s
goto ret_close;
}
- /* Currently we send full-sized DHCP packets (see above) */
- result = safe_write(fd, payload, DHCP_SIZE);
+ result = safe_write(fd, payload, udhcp_get_payload_len(payload));
msg = "write";
ret_close:
close(fd);
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