Em Thu, Aug 28, 2008 at 07:44:47PM +0200, Gerrit Renker escreveu:
> This provides feature negotiation for server minimum checksum coverage
> which so far has been missing.
>
> Since sender/receiver coverage values range only from 0...15, their
> type has also been reduced in size from u16 to u4.
>
> Feature-negotiation options are now generated for both sender and receiver
> coverage, i.e. when the peer has `forgotten' to enable partial coverage
> then feature negotiation will automatically enable (negotiate) the partial
> coverage value for this connection.
>
> Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
> Acked-by: Ian McDonald <ian.mcdonald@xxxxxxxxxxx>
> ---
> include/linux/dccp.h | 4 +-
> net/dccp/proto.c | 52 +++++++++++++++++++++++++++++++++++++------------
> 2 files changed, 41 insertions(+), 15 deletions(-)
>
> --- a/include/linux/dccp.h
> +++ b/include/linux/dccp.h
> @@ -527,8 +527,8 @@ struct dccp_sock {
> __u32 dccps_timestamp_time;
> __u16 dccps_l_ack_ratio;
> __u16 dccps_r_ack_ratio;
> - __u16 dccps_pcslen;
> - __u16 dccps_pcrlen;
> + __u8 dccps_pcslen:4;
> + __u8 dccps_pcrlen:4;
> __u64 dccps_ndp_count:48;
> unsigned long dccps_rate_last;
> struct dccp_minisock dccps_minisock;
> --- a/net/dccp/proto.c
> +++ b/net/dccp/proto.c
> @@ -470,6 +470,41 @@ static int dccp_setsockopt_service(struct sock *sk, const __be32 service,
> return 0;
> }
>
> +static int dccp_setsockopt_cscov(struct sock *sk, int cscov, bool rx)
> +{
> + u8 *list, len;
> + int i, rc;
> +
> + if (cscov < 0 || cscov > 15)
> + return -EINVAL;
> +
> + if (rx)
> + dccp_sk(sk)->dccps_pcrlen = cscov;
> + else
> + dccp_sk(sk)->dccps_pcslen = cscov;
Wouldn't be better to change socket internal state only after the
kmalloc? Perhaps even only if dccp_feat_register_sp was successful?
> + /*
> + * Populate a list of permissible values, in the range cscov...15. This
> + * is necessary since feature negotiation of single values only works if
> + * both sides incidentally choose the same value. Since the list starts
> + * lowest-value first, negotiation will pick the smallest shared value.
> + */
> + if (cscov == 0)
> + return 0;
> + len = 16 - cscov;
> +
> + list = kmalloc(len, GFP_KERNEL);
> + if (list == NULL)
> + return -ENOBUFS;
> +
> + for (i = 0; i < len; i++)
> + list[i] = cscov++;
> +
> + rc = dccp_feat_register_sp(sk, DCCPF_MIN_CSUM_COVER, rx, list, len);
> +
> + kfree(list);
> + return rc;
> +}
> +
> static int do_dccp_setsockopt(struct sock *sk, int level, int optname,
> char __user *optval, int optlen)
> {
> @@ -502,20 +537,11 @@ static int do_dccp_setsockopt(struct sock *sk, int level, int optname,
> else
> dp->dccps_server_timewait = (val != 0);
> break;
> - case DCCP_SOCKOPT_SEND_CSCOV: /* sender side, RFC 4340, sec. 9.2 */
> - if (val < 0 || val > 15)
> - err = -EINVAL;
> - else
> - dp->dccps_pcslen = val;
> + case DCCP_SOCKOPT_SEND_CSCOV:
> + err = dccp_setsockopt_cscov(sk, val, false);
> break;
> - case DCCP_SOCKOPT_RECV_CSCOV: /* receiver side, RFC 4340 sec. 9.2.1 */
> - if (val < 0 || val > 15)
> - err = -EINVAL;
> - else {
> - dp->dccps_pcrlen = val;
> - /* FIXME: add feature negotiation,
> - * ChangeL(MinimumChecksumCoverage, val) */
> - }
> + case DCCP_SOCKOPT_RECV_CSCOV:
> + err = dccp_setsockopt_cscov(sk, val, true);
> break;
> default:
> err = -ENOPROTOOPT;
> --
> 1.6.0.rc2
>
> --
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