X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Flibsystemd-network%2Fdhcp-packet.c;h=fba9c46ef226fd9e3cf4d0bdbe2b67879c0e3aac;hp=4f90c283a21485a686b18704dbf1227b2a058d46;hb=d576127429a7be7d8e393d06f1bdd004fa37096c;hpb=2ad7561f9f658f8dee168a76654c7d918e2260c7

diff --git a/src/libsystemd-network/dhcp-packet.c b/src/libsystemd-network/dhcp-packet.c
index 4f90c283a..fba9c46ef 100644
--- a/src/libsystemd-network/dhcp-packet.c
+++ b/src/libsystemd-network/dhcp-packet.c
@@ -43,23 +43,13 @@ int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid,
 
         assert(op == BOOTREQUEST || op == BOOTREPLY);
 
-        *opt = (uint8_t *)(message + 1);
-
-        if (*optlen < 4)
-                return -ENOBUFS;
-        *optlen -= 4;
-
         message->op = op;
         message->htype = ARPHRD_ETHER;
         message->hlen = ETHER_ADDR_LEN;
         message->xid = htobe32(xid);
+        message->magic = htobe32(DHCP_MAGIC_COOKIE);
 
-        (*opt)[0] = 0x63;
-        (*opt)[1] = 0x82;
-        (*opt)[2] = 0x53;
-        (*opt)[3] = 0x63;
-
-        *opt += 4;
+        *opt = (uint8_t *)(message + 1);
 
         err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
                                  &type);
@@ -69,21 +59,48 @@ int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid,
         return 0;
 }
 
-uint16_t dhcp_packet_checksum(void *buf, int len) {
-        uint32_t sum;
-        uint16_t *check;
-        int i;
-        uint8_t *odd;
+uint16_t dhcp_packet_checksum(void *buf, size_t len) {
+        uint64_t *buf_64 = buf;
+        uint64_t *end_64 = (uint64_t*)buf + (len / sizeof(uint64_t));
+        uint32_t *buf_32;
+        uint16_t *buf_16;
+        uint8_t *buf_8;
+        uint64_t sum = 0;
+
+        while (buf_64 < end_64) {
+                sum += *buf_64;
+                if (sum < *buf_64)
+                        sum++;
+
+                buf_64 ++;
+        }
+
+        buf_32 = (uint32_t*)buf_64;
+
+        if (len & sizeof(uint32_t)) {
+                sum += *buf_32;
+                if (sum < *buf_32)
+                        sum++;
+
+                buf_32 ++;
+        }
 
-        sum = 0;
-        check = buf;
+        buf_16 = (uint16_t*)buf_32;
 
-        for (i = 0; i < len / 2 ; i++)
-                sum += check[i];
+        if (len & sizeof(uint16_t)) {
+                sum += *buf_16;
+                if (sum < *buf_16)
+                        sum ++;
 
-        if (len & 0x01) {
-                odd = buf;
-                sum += odd[len - 1];
+                buf_16 ++;
+        }
+
+        buf_8 = (uint8_t*)buf_16;
+
+        if (len & sizeof(uint8_t)) {
+                sum += *buf_8;
+                if (sum < *buf_8)
+                        sum++;
         }
 
         while (sum >> 16)
@@ -123,13 +140,6 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) {
 
         /* IP */
 
-        if (len < DHCP_IP_SIZE) {
-                log_dhcp_client(client, "ignoring packet: packet (%zu bytes) "
-                                " smaller than IP header (%u bytes)", len,
-                                DHCP_IP_SIZE);
-                return -EINVAL;
-        }
-
         if (packet->ip.version != IPVERSION) {
                 log_dhcp_client(client, "ignoring packet: not IPv4");
                 return -EINVAL;
@@ -162,13 +172,6 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) {
                 return -EINVAL;
         }
 
-        if (len < DHCP_IP_UDP_SIZE) {
-                log_dhcp_client(client, "ignoring packet: packet (%zu bytes) "
-                                " smaller than IP+UDP header (%u bytes)", len,
-                                DHCP_IP_UDP_SIZE);
-                return -EINVAL;
-        }
-
         if (len < hdrlen + be16toh(packet->udp.len)) {
                 log_dhcp_client(client, "ignoring packet: packet (%zu bytes) "
                                 "smaller than expected (%zu) by UDP header", len,