Looks good to me.
Ethan
On Fri, Oct 7, 2011 at 15:45, Ben Pfaff <b...@nicira.com> wrote:
> Wireshark complained that Open vSwitch-generated CFM messages were
> malformed. Upon looking at the standard, I spotted that Open vSwitch
> failed to include the final, required "End TLV" byte with value 0.
>
> This commit adds the End TLV byte to generated CCMs but still accepts
> the truncated messages for backward compatibility.
> ---
> lib/cfm.c | 15 ++++++++++++---
> 1 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/lib/cfm.c b/lib/cfm.c
> index 3f3dcd2..bdd3839 100644
> --- a/lib/cfm.c
> +++ b/lib/cfm.c
> @@ -49,8 +49,13 @@ static const uint8_t eth_addr_ccm_x[6] = {
>
> /* A 'ccm' represents a Continuity Check Message from the 802.1ag
> * specification. Continuity Check Messages are broadcast periodically so
> that
> - * hosts can determine whom they have connectivity to. */
> -#define CCM_LEN 74
> + * hosts can determine whom they have connectivity to.
> + *
> + * The minimum length of a CCM as specified by IEEE 802.1ag is 75 bytes.
> + * Previous versions of Open vSwitch generated 74-byte CCM messages, so we
> + * accept such messages too. */
> +#define CCM_LEN 75
> +#define CCM_ACCEPT_LEN 74
> #define CCM_MAID_LEN 48
> #define CCM_OPCODE 1 /* CFM message opcode meaning CCM. */
> #define CCM_RDI_MASK 0x80
> @@ -67,6 +72,9 @@ struct ccm {
> ovs_be16 interval_ms_x; /* Transmission interval in ms. */
> ovs_be64 mpid64; /* MPID in extended mode. */
> uint8_t zero[6];
> +
> + /* TLV space. */
> + uint8_t end_tlv;
> } __attribute__((packed));
> BUILD_ASSERT_DECL(CCM_LEN == sizeof(struct ccm));
>
> @@ -336,6 +344,7 @@ cfm_compose_ccm(struct cfm *cfm, struct ofpbuf *packet,
> ccm->flags = cfm->ccm_interval;
> memcpy(ccm->maid, cfm->maid, sizeof ccm->maid);
> memset(ccm->zero, 0, sizeof ccm->zero);
> + ccm->end_tlv = 0;
>
> if (cfm->extended) {
> ccm->mpid = htons(hash_mpid(cfm->mpid));
> @@ -412,7 +421,7 @@ cfm_process_heartbeat(struct cfm *cfm, const struct
> ofpbuf *p)
> struct eth_header *eth;
>
> eth = p->l2;
> - ccm = ofpbuf_at(p, (uint8_t *)p->l3 - (uint8_t *)p->data, CCM_LEN);
> + ccm = ofpbuf_at(p, (uint8_t *)p->l3 - (uint8_t *)p->data,
> CCM_ACCEPT_LEN);
>
> if (!ccm) {
> VLOG_INFO_RL(&rl, "%s: Received an unparseable 802.1ag CCM
> heartbeat.",
> --
> 1.7.4.4
>
> _______________________________________________
> dev mailing list
> dev@openvswitch.org
> http://openvswitch.org/mailman/listinfo/dev
>
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