diff options
| author | Ben Pfaff <blp@nicira.com> | 2011-03-29 09:28:49 -0700 |
|---|---|---|
| committer | Ben Pfaff <blp@nicira.com> | 2011-04-01 15:52:19 -0700 |
| commit | eda1f38d41be1b604229343fe14d7122eaedd4d5 (patch) | |
| tree | 90d61189e7937cf83280c8f3528c27a2a193d1e8 /lib/packets.c | |
| parent | 7c66b273a2addd3f6c60b6c930464d6be74df71e (diff) | |
packets: Reserve headroom for VLAN header in eth_compose(), snap_compose().
This allows callers to add a VLAN header to the composed packet and send
it out on a VLAN without copying the whole payload.
Diffstat (limited to 'lib/packets.c')
| -rw-r--r-- | lib/packets.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/lib/packets.c b/lib/packets.c index 83c852c1..d2229cd2 100644 --- a/lib/packets.c +++ b/lib/packets.c @@ -221,7 +221,10 @@ ipv6_is_cidr(const struct in6_addr *netmask) /* Populates 'b' with an Ethernet II packet headed with the given 'eth_dst', * 'eth_src' and 'eth_type' parameters. A payload of 'size' bytes is allocated * in 'b' and returned. This payload may be populated with appropriate - * information by the caller. */ + * information by the caller. + * + * The returned packet has enough headroom to insert an 802.1Q VLAN header if + * desired. */ void * eth_compose(struct ofpbuf *b, const uint8_t eth_dst[ETH_ADDR_LEN], const uint8_t eth_src[ETH_ADDR_LEN], uint16_t eth_type, @@ -232,7 +235,8 @@ eth_compose(struct ofpbuf *b, const uint8_t eth_dst[ETH_ADDR_LEN], ofpbuf_clear(b); - ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + size); + ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + VLAN_HEADER_LEN + size); + ofpbuf_reserve(b, VLAN_HEADER_LEN); eth = ofpbuf_put_uninit(b, ETH_HEADER_LEN); data = ofpbuf_put_uninit(b, size); @@ -246,7 +250,10 @@ eth_compose(struct ofpbuf *b, const uint8_t eth_dst[ETH_ADDR_LEN], /* Populates 'b' with an Ethernet LLC+SNAP packet headed with the given * 'eth_dst', 'eth_src', 'snap_org', and 'snap_type'. A payload of 'size' * bytes is allocated in 'b' and returned. This payload may be populated with - * appropriate information by the caller. */ + * appropriate information by the caller. + * + * The returned packet has enough headroom to insert an 802.1Q VLAN header if + * desired. */ void * snap_compose(struct ofpbuf *b, const uint8_t eth_dst[ETH_ADDR_LEN], const uint8_t eth_src[ETH_ADDR_LEN], @@ -259,7 +266,9 @@ snap_compose(struct ofpbuf *b, const uint8_t eth_dst[ETH_ADDR_LEN], /* Compose basic packet structure. (We need the payload size to stick into * the 802.2 header.) */ ofpbuf_clear(b); - ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + LLC_SNAP_HEADER_LEN + size); + ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + VLAN_HEADER_LEN + + LLC_SNAP_HEADER_LEN + size); + ofpbuf_reserve(b, VLAN_HEADER_LEN); eth = ofpbuf_put_zeros(b, ETH_HEADER_LEN); llc_snap = ofpbuf_put_zeros(b, LLC_SNAP_HEADER_LEN); payload = ofpbuf_put_uninit(b, size); |