[systemd-commits] 3 commits - src/libsystemd-network

[Tom Gundersen]

 src/libsystemd-network/dhcp-packet.c |   36 ++++++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 11 deletions(-)

New commits:
commit 2ad7561f9f658f8dee168a76654c7d918e2260c7
Author: Tom Gundersen <teg at jklm.no>
Date:   Sun Mar 30 20:36:44 2014 +0200

    sd-dhcp: avoid checksum calculation if possible
    
    When receiving lots of packets that are not meant for us, we waste a relatively large amount
    of cpu time computing their checksums before discarding them. Move the checksum calculation last
    so we never compute it for packets which would otherwise be discarded.

diff --git a/src/libsystemd-network/dhcp-packet.c b/src/libsystemd-network/dhcp-packet.c
index 3b62c25..4f90c28 100644
--- a/src/libsystemd-network/dhcp-packet.c
+++ b/src/libsystemd-network/dhcp-packet.c
@@ -155,11 +155,6 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) {
                 return -EINVAL;
         }
 
-        if (dhcp_packet_checksum(&packet->ip, hdrlen)) {
-                log_dhcp_client(client, "ignoring packet: invalid IP checksum");
-                return -EINVAL;
-        }
-
         /* UDP */
 
         if (packet->ip.protocol != IPPROTO_UDP) {
@@ -181,6 +176,22 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) {
                 return -EINVAL;
         }
 
+        if (be16toh(packet->udp.dest) != DHCP_PORT_CLIENT) {
+                log_dhcp_client(client, "ignoring packet: to port %u, which "
+                                "is not the DHCP client port (%u)",
+                                be16toh(packet->udp.dest), DHCP_PORT_CLIENT);
+                return -EINVAL;
+        }
+
+        /* checksums - computing these is relatively expensive, so only do it
+           if all the other checks have passed
+         */
+
+        if (dhcp_packet_checksum(&packet->ip, hdrlen)) {
+                log_dhcp_client(client, "ignoring packet: invalid IP checksum");
+                return -EINVAL;
+        }
+
         if (checksum && packet->udp.check) {
                 packet->ip.check = packet->udp.len;
                 packet->ip.ttl = 0;
@@ -192,12 +203,5 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) {
                 }
         }
 
-        if (be16toh(packet->udp.dest) != DHCP_PORT_CLIENT) {
-                log_dhcp_client(client, "ignoring packet: to port %u, which "
-                                "is not the DHCP client port (%u)",
-                                be16toh(packet->udp.dest), DHCP_PORT_CLIENT);
-                return -EINVAL;
-        }
-
         return 0;
 }

commit 6e34949d7207f9dff4e2b01a3037a0af88e1c25c
Author: Tom Gundersen <teg at jklm.no>
Date:   Sun Mar 30 20:33:57 2014 +0200

    sd-dhcp: check for ipv4 packets

diff --git a/src/libsystemd-network/dhcp-packet.c b/src/libsystemd-network/dhcp-packet.c
index 9779cbd..3b62c25 100644
--- a/src/libsystemd-network/dhcp-packet.c
+++ b/src/libsystemd-network/dhcp-packet.c
@@ -130,6 +130,11 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) {
                 return -EINVAL;
         }
 
+        if (packet->ip.version != IPVERSION) {
+                log_dhcp_client(client, "ignoring packet: not IPv4");
+                return -EINVAL;
+        }
+
         if (packet->ip.ihl < 5) {
                 log_dhcp_client(client, "ignoring packet: IPv4 IHL (%u words) invalid",
                                 packet->ip.ihl);

commit d454a6748c34f0f67eef618238e0a64b80c85303
Author: Umut Tezduyar Lindskog <umut.tezduyar at axis.com>
Date:   Sun Mar 30 19:09:14 2014 +0200

    sd-dhcp: check for udp packets
    
    Do not try to parse ICMP packets
    
    [tomegun: slightly tweaked debug message]

diff --git a/src/libsystemd-network/dhcp-packet.c b/src/libsystemd-network/dhcp-packet.c
index bed942f..9779cbd 100644
--- a/src/libsystemd-network/dhcp-packet.c
+++ b/src/libsystemd-network/dhcp-packet.c
@@ -157,6 +157,11 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum) {
 
         /* UDP */
 
+        if (packet->ip.protocol != IPPROTO_UDP) {
+                log_dhcp_client(client, "ignoring packet: not UDP");
+                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,