mirror of https://github.com/hak5/openwrt.git
76 lines
2.6 KiB
Diff
76 lines
2.6 KiB
Diff
--- a/networking/udhcp/packet.c
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+++ b/networking/udhcp/packet.c
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@@ -120,6 +120,10 @@ uint16_t FAST_FUNC udhcp_checksum(void *
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return ~sum;
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}
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+int udhcp_get_payload_len(struct dhcpMessage *payload)
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+{
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+ return sizeof(struct dhcpMessage) - DHCP_OPTIONS_BUFSIZE + end_option(payload->options) + sizeof(payload->options[0]);
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+}
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/* Construct a ip/udp header for a packet, send packet */
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int FAST_FUNC udhcp_send_raw_packet(struct dhcpMessage *payload,
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@@ -132,11 +136,7 @@ int FAST_FUNC udhcp_send_raw_packet(stru
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int fd;
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int result = -1;
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const char *msg;
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-
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- enum {
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- IP_UPD_DHCP_SIZE = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
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- UPD_DHCP_SIZE = IP_UPD_DHCP_SIZE - offsetof(struct udp_dhcp_packet, udp),
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- };
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+ int p_len = udhcp_get_payload_len(payload);
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fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
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if (fd < 0) {
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@@ -146,7 +146,7 @@ int FAST_FUNC udhcp_send_raw_packet(stru
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memset(&dest, 0, sizeof(dest));
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memset(&packet, 0, sizeof(packet));
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- packet.data = *payload; /* struct copy */
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+ memcpy(&(packet.data), payload, p_len);
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dest.sll_family = AF_PACKET;
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dest.sll_protocol = htons(ETH_P_IP);
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@@ -163,23 +163,18 @@ int FAST_FUNC udhcp_send_raw_packet(stru
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packet.ip.daddr = dest_ip;
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packet.udp.source = htons(source_port);
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packet.udp.dest = htons(dest_port);
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- /* size, excluding IP header: */
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- packet.udp.len = htons(UPD_DHCP_SIZE);
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- /* for UDP checksumming, ip.len is set to UDP packet len */
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+ p_len += sizeof(packet.udp);
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+ packet.udp.len = htons(p_len);
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packet.ip.tot_len = packet.udp.len;
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- packet.udp.check = udhcp_checksum(&packet, IP_UPD_DHCP_SIZE);
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- /* but for sending, it is set to IP packet len */
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- packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE);
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+ p_len += sizeof(packet.ip);
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+ packet.udp.check = udhcp_checksum(&packet, p_len);
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+ packet.ip.tot_len = htons(p_len);
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packet.ip.ihl = sizeof(packet.ip) >> 2;
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packet.ip.version = IPVERSION;
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packet.ip.ttl = IPDEFTTL;
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packet.ip.check = udhcp_checksum(&packet.ip, sizeof(packet.ip));
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- /* Currently we send full-sized DHCP packets (zero padded).
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- * If you need to change this: last byte of the packet is
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- * packet.data.options[end_option(packet.data.options)]
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- */
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- result = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0,
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+ result = sendto(fd, &packet, p_len, 0,
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(struct sockaddr *) &dest, sizeof(dest));
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msg = "sendto";
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ret_close:
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@@ -231,8 +226,7 @@ int FAST_FUNC udhcp_send_kernel_packet(s
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goto ret_close;
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}
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- /* Currently we send full-sized DHCP packets (see above) */
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- result = safe_write(fd, payload, DHCP_SIZE);
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+ result = safe_write(fd, payload, udhcp_get_payload_len(payload));
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msg = "write";
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ret_close:
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close(fd);
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