[systemd-devel] [PATCH 2/2] dhcp-network: don't bother with IP fragments

[Michal Sekletar]

---
 src/libsystemd-network/dhcp-network.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/libsystemd-network/dhcp-network.c b/src/libsystemd-network/dhcp-network.c
index e5fd6a8..f500bff 100644
--- a/src/libsystemd-network/dhcp-network.c
+++ b/src/libsystemd-network/dhcp-network.c
@@ -41,6 +41,10 @@ int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link,
             BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.protocol)), /* A <- IP protocol */
             BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0),                /* IP protocol == UDP ? */
             BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
+            BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags + Fragment offset */
+            BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff),                           /* A <- A & 0x1fff */
+            BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0),                          /* A == 0 ? */
+            BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
             BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, udp.dest)),    /* A <- UDP destination port */
             BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_PORT_CLIENT, 1, 0),           /* UDP destination port == DHCP client port ? */
             BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
-- 
2.0.0