diff options
| author | Vadim Kochan <vadim4j@gmail.com> | 2016-08-05 15:04:38 +0200 |
|---|---|---|
| committer | Tobias Klauser <tklauser@distanz.ch> | 2016-08-05 15:09:01 +0200 |
| commit | a0e2b28801d2ddb5ccf80a7c5d0b9ac9b75f736d (patch) | |
| tree | 3b8f27a81ebec2d53e561fab9961024fc0217088 | |
| parent | b073c8e5fd7f8c723680b659bd81afd231ef32f5 (diff) | |
trafgen: proto: Use field id as array index
Usually proto fields array are sorted in the same order as the
respective enum. Thus, the id can be used used as an array index for
faster lookup.
Add an explanatory comment and enforce the correspondence of id and
index using bug_on().
This will make csum field calculation a little faster at runtime.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
| -rw-r--r-- | trafgen_l3.h | 4 | ||||
| -rw-r--r-- | trafgen_proto.c | 11 |
2 files changed, 7 insertions, 8 deletions
diff --git a/trafgen_l3.h b/trafgen_l3.h index a1b1523..e0c9a1c 100644 --- a/trafgen_l3.h +++ b/trafgen_l3.h @@ -10,14 +10,14 @@ enum ip4_field { IP4_LEN, IP4_ID, IP4_FLAGS, + IP4_MF, + IP4_DF, IP4_FRAG_OFFS, IP4_TTL, IP4_PROTO, IP4_CSUM, IP4_SADDR, IP4_DADDR, - IP4_DF, - IP4_MF, }; enum ip6_field { diff --git a/trafgen_proto.c b/trafgen_proto.c index e08c9c2..212e968 100644 --- a/trafgen_proto.c +++ b/trafgen_proto.c @@ -107,13 +107,12 @@ void proto_header_fields_add(struct proto_hdr *hdr, static struct proto_field *proto_field_by_id(struct proto_hdr *hdr, uint32_t fid) { - int i; - - for (i = 0; i < hdr->fields_count; i++) - if (hdr->fields[i].id == fid) - return &hdr->fields[i]; + /* Assume the fields are stored in the same order as the respective + * enum, so the index can be used for faster lookup here. + */ + bug_on(hdr->fields[fid].id != fid); - panic("Failed lookup field id %u for proto id %u\n", fid, hdr->id); + return &hdr->fields[fid]; } bool proto_field_is_set(struct proto_hdr *hdr, uint32_t fid) |