mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-22 15:02:32 +00:00
100 lines
3.4 KiB
Diff
100 lines
3.4 KiB
Diff
--- a/networking/udhcp/packet.c
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+++ b/networking/udhcp/packet.c
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@@ -158,6 +158,11 @@ 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 dhcp_packet *dhcp_pkt)
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+{
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+ return sizeof(struct dhcp_packet) - DHCP_OPTIONS_BUFSIZE + udhcp_end_option(dhcp_pkt->options) + sizeof(dhcp_pkt->options[0]);
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+}
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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 dhcp_packet *dhcp_pkt,
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uint32_t source_nip, int source_port,
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@@ -166,10 +171,10 @@ int FAST_FUNC udhcp_send_raw_packet(stru
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{
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struct sockaddr_ll dest_sll;
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struct ip_udp_dhcp_packet packet;
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- unsigned padding;
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int fd;
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int result = -1;
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const char *msg;
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+ int p_len = udhcp_get_payload_len(dhcp_pkt);
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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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@@ -178,8 +183,8 @@ int FAST_FUNC udhcp_send_raw_packet(stru
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}
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memset(&dest_sll, 0, sizeof(dest_sll));
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- memset(&packet, 0, offsetof(struct ip_udp_dhcp_packet, data));
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- packet.data = *dhcp_pkt; /* struct copy */
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+ memset(&packet, 0, sizeof(packet));
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+ memcpy(&(packet.data), dhcp_pkt, p_len);
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dest_sll.sll_family = AF_PACKET;
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dest_sll.sll_protocol = htons(ETH_P_IP);
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@@ -192,36 +197,24 @@ int FAST_FUNC udhcp_send_raw_packet(stru
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goto ret_close;
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}
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- /* We were sending full-sized DHCP packets (zero padded),
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- * but some badly configured servers were seen dropping them.
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- * Apparently they drop all DHCP packets >576 *ethernet* octets big,
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- * whereas they may only drop packets >576 *IP* octets big
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- * (which for typical Ethernet II means 590 octets: 6+6+2 + 576).
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- *
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- * In order to work with those buggy servers,
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- * we truncate packets after end option byte.
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- */
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- padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(packet.data.options);
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-
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packet.ip.protocol = IPPROTO_UDP;
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packet.ip.saddr = source_nip;
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packet.ip.daddr = dest_nip;
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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(UDP_DHCP_SIZE - padding);
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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_UDP_DHCP_SIZE - padding);
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- /* but for sending, it is set to IP packet len */
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- packet.ip.tot_len = htons(IP_UDP_DHCP_SIZE - padding);
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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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udhcp_dump_packet(dhcp_pkt);
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- result = sendto(fd, &packet, IP_UDP_DHCP_SIZE - padding, /*flags:*/ 0,
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+ result = sendto(fd, &packet, p_len, /*flags:*/ 0,
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(struct sockaddr *) &dest_sll, sizeof(dest_sll));
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msg = "sendto";
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ret_close:
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@@ -239,7 +232,6 @@ int FAST_FUNC udhcp_send_kernel_packet(s
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uint32_t dest_nip, int dest_port)
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{
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struct sockaddr_in client;
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- unsigned padding;
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int fd;
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int result = -1;
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const char *msg;
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@@ -270,9 +262,7 @@ int FAST_FUNC udhcp_send_kernel_packet(s
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}
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udhcp_dump_packet(dhcp_pkt);
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-
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- padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(dhcp_pkt->options);
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- result = safe_write(fd, dhcp_pkt, DHCP_SIZE - padding);
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+ result = safe_write(fd, dhcp_pkt, udhcp_get_payload_len(dhcp_pkt));
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msg = "write";
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ret_close:
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close(fd);
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