diff options
| author | Michal Sekletar <msekleta@redhat.com> | 2014-07-07 15:27:24 +0200 |
|---|---|---|
| committer | Michal Sekletar <msekleta@redhat.com> | 2014-07-07 15:59:13 +0200 |
| commit | ffc90a11962274ac597b7838f31a4aff0362aa46 (patch) | |
| tree | 4018c4717b48fe6d5aa05fb916a8831b01143b79 | |
| parent | b064329fd80b8d0fe2e46c561f92886090fa20d1 (diff) | |
dhcp-network: make clear that we are ANDing Fragment offset field with mask
Reading BPF assembly written as C macros is inherently difficult. Don't
make it harder than necessary and provide clearer explanation in the
comment.
| -rw-r--r-- | src/libsystemd-network/dhcp-network.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/libsystemd-network/dhcp-network.c b/src/libsystemd-network/dhcp-network.c index 17020b0a00..16411cc41a 100644 --- a/src/libsystemd-network/dhcp-network.c +++ b/src/libsystemd-network/dhcp-network.c @@ -46,7 +46,7 @@ int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link, 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, ip.frag_off)), /* A <- Flags + Fragment offset */ - BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff), /* A <- A & 0x1fff */ + BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff), /* A <- A & 0x1fff (Fragment offset) */ 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 */ |