Subject: Re: [PATCH nf-next] netfilter: nf_ct_sctp: minimal multihoming support

From: Florian Westphal <[email-masked]>
Date: Tue, 14 Jul 2015 15:42:03 +0200

Michal Kubecek <[email-masked]> wrote:
> +	case SCTP_CID_HEARTBEAT:
> +		pr_debug("SCTP_CID_HEARTBEAT");
> +		i = 9;
> +		break;
> +	case SCTP_CID_HEARTBEAT_ACK:
> +		pr_debug("SCTP_CID_HEARTBEAT_ACK");
> +		i = 10;
> +		break;
>  	default:
>  		/* Other chunks like DATA, SACK, HEARTBEAT and
>  		its ACK do not cause a change in state */
> @@ -329,6 +351,8 @@ static int sctp_packet(struct nf_conn *ct,
>  	    !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
>  	    !test_bit(SCTP_CID_ABORT, map) &&
>  	    !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
> +	    !test_bit(SCTP_CID_HEARTBEAT, map) &&
> +	    !test_bit(SCTP_CID_HEARTBEAT_ACK, map) &&
>  	    sh->vtag != ct->proto.sctp.vtag[dir]) {
>  		pr_debug("Verification tag check failed\n");
>  		goto out;
> @@ -357,6 +381,16 @@ static int sctp_packet(struct nf_conn *ct,
>  			/* Sec 8.5.1 (D) */
>  			if (sh->vtag != ct->proto.sctp.vtag[dir])
>  				goto out_unlock;
> +		} else if (sch->type == SCTP_CID_HEARTBEAT ||
> +			   sch->type == SCTP_CID_HEARTBEAT_ACK) {
> +			if (ct->proto.sctp.vtag[dir] == 0) {
> +				pr_debug("Setting vtag %x for dir %d\n",
> +					 sh->vtag, dir);
> +				ct->proto.sctp.vtag[dir] = sh->vtag;

Could you please elaborate on the [dir] == 0 test?

I see this might happen for SCTP_CID_HEARTBEAT_ACK, but why is this
needed for SCTP_CID_HEARTBEAT ?

We found a conntrack entry so shouldn't the vtag[dir] already be > 0?