Root/package/busybox/patches/241-udhcpc-oversized_packets.patch

1--- a/networking/udhcp/packet.c
2+++ b/networking/udhcp/packet.c
3@@ -164,6 +164,11 @@ uint16_t FAST_FUNC udhcp_checksum(void *
4     return ~sum;
5 }
6 
7+int udhcp_get_payload_len(struct dhcp_packet *dhcp_pkt)
8+{
9+ return sizeof(struct dhcp_packet) - DHCP_OPTIONS_BUFSIZE + end_option(dhcp_pkt->options) + sizeof(dhcp_pkt->options[0]);
10+}
11+
12 /* Construct a ip/udp header for a packet, send packet */
13 int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
14         uint32_t source_ip, int source_port,
15@@ -175,11 +180,7 @@ int FAST_FUNC udhcp_send_raw_packet(stru
16     int fd;
17     int result = -1;
18     const char *msg;
19-
20- enum {
21- IP_UPD_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
22- UPD_DHCP_SIZE = IP_UPD_DHCP_SIZE - offsetof(struct ip_udp_dhcp_packet, udp),
23- };
24+ int p_len = udhcp_get_payload_len(dhcp_pkt);
25 
26     fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
27     if (fd < 0) {
28@@ -189,7 +190,7 @@ int FAST_FUNC udhcp_send_raw_packet(stru
29 
30     memset(&dest, 0, sizeof(dest));
31     memset(&packet, 0, sizeof(packet));
32- packet.data = *dhcp_pkt; /* struct copy */
33+ memcpy(&(packet.data), dhcp_pkt, p_len);
34 
35     dest.sll_family = AF_PACKET;
36     dest.sll_protocol = htons(ETH_P_IP);
37@@ -206,24 +207,19 @@ int FAST_FUNC udhcp_send_raw_packet(stru
38     packet.ip.daddr = dest_ip;
39     packet.udp.source = htons(source_port);
40     packet.udp.dest = htons(dest_port);
41- /* size, excluding IP header: */
42- packet.udp.len = htons(UPD_DHCP_SIZE);
43- /* for UDP checksumming, ip.len is set to UDP packet len */
44+ p_len += sizeof(packet.udp);
45+ packet.udp.len = htons(p_len);
46     packet.ip.tot_len = packet.udp.len;
47- packet.udp.check = udhcp_checksum(&packet, IP_UPD_DHCP_SIZE);
48- /* but for sending, it is set to IP packet len */
49- packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE);
50+ p_len += sizeof(packet.ip);
51+ packet.udp.check = udhcp_checksum(&packet, p_len);
52+ packet.ip.tot_len = htons(p_len);
53     packet.ip.ihl = sizeof(packet.ip) >> 2;
54     packet.ip.version = IPVERSION;
55     packet.ip.ttl = IPDEFTTL;
56     packet.ip.check = udhcp_checksum(&packet.ip, sizeof(packet.ip));
57 
58- /* Currently we send full-sized DHCP packets (zero padded).
59- * If you need to change this: last byte of the packet is
60- * packet.data.options[end_option(packet.data.options)]
61- */
62     udhcp_dump_packet(dhcp_pkt);
63- result = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0,
64+ result = sendto(fd, &packet, p_len, 0,
65                 (struct sockaddr *) &dest, sizeof(dest));
66     msg = "sendto";
67  ret_close:
68@@ -245,10 +241,6 @@ int FAST_FUNC udhcp_send_kernel_packet(s
69     int result = -1;
70     const char *msg;
71 
72- enum {
73- DHCP_SIZE = sizeof(struct dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
74- };
75-
76     fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
77     if (fd < 0) {
78         msg = "socket(%s)";
79@@ -274,9 +266,8 @@ int FAST_FUNC udhcp_send_kernel_packet(s
80         goto ret_close;
81     }
82 
83- /* Currently we send full-sized DHCP packets (see above) */
84     udhcp_dump_packet(dhcp_pkt);
85- result = safe_write(fd, dhcp_pkt, DHCP_SIZE);
86+ result = safe_write(fd, dhcp_pkt, udhcp_get_payload_len(dhcp_pkt));
87     msg = "write";
88  ret_close:
89     close(fd);
90

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