diff options
| author | Tom Gundersen <teg@jklm.no> | 2014-04-06 19:23:33 +0200 |
|---|---|---|
| committer | Tom Gundersen <teg@jklm.no> | 2014-04-06 19:42:11 +0200 |
| commit | 7429b07f822348dc5a87208ce107f5f6bf02656d (patch) | |
| tree | ce9b61db02a34ba440dcc35385b9151e37754fee /src/libsystemd-network/dhcp-network.c | |
| parent | 0c79c68d93d721d37ba088fb50dbf07bb0d447e5 (diff) | |
sd-dhcp-client: improve BPF
Try a bit harder to make the kernel drop packets not for us. This should reduce
the number of wakeups from n^2 to n in the number of dhcp clients, which admittedly
only makes a differenc in very extreme cases.
Diffstat (limited to 'src/libsystemd-network/dhcp-network.c')
| -rw-r--r-- | src/libsystemd-network/dhcp-network.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/src/libsystemd-network/dhcp-network.c b/src/libsystemd-network/dhcp-network.c index a9a15b4d5a..902c9d9be2 100644 --- a/src/libsystemd-network/dhcp-network.c +++ b/src/libsystemd-network/dhcp-network.c @@ -23,6 +23,7 @@ #include <string.h> #include <linux/if_packet.h> #include <net/ethernet.h> +#include <net/if_arp.h> #include <stdio.h> #include <unistd.h> #include <linux/filter.h> @@ -31,18 +32,34 @@ #include "dhcp-internal.h" -int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link) -{ +int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link, uint32_t xid) { struct sock_filter filter[] = { BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), /* A <- packet length */ BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(DHCPPacket), 1, 0), /* packet >= DHCPPacket ? */ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + /* TODO: match ip.version */ 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, 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 */ + BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.op)), /* A <- DHCP op */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, BOOTREPLY, 1, 0), /* op == BOOTREPLY ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.htype)), /* A <- DHCP header type */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0), /* header type == ARPHRD_ETHER ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.hlen)), /* A <- mac address length */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHER_ADDR_LEN, 1, 0), /* address length == ETHER_ADDR_LEN ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.xid)), /* A <- client identifier */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, xid, 1, 0), /* client identifier == xid ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + /* TODO: match chaddr */ + BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.magic)), /* A <- DHCP magic cookie */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_MAGIC_COOKIE, 1, 0), /* cookie == DHCP magic cookie ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */ }; struct sock_fprog fprog = { |