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author | Gerrit Renker <gerrit@erg.abdn.ac.uk> | 2010-11-10 21:21:02 +0100 |
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committer | Gerrit Renker <gerrit@erg.abdn.ac.uk> | 2010-11-10 21:21:02 +0100 |
commit | 7d870936602533836bba821bd5c679c62c52a95f (patch) | |
tree | 35ffc317699b1700b27dfd8c5da4512d87848e65 /net/dccp/options.c | |
parent | f17a37c9b8c4b32c01e501a84fa6f30e344c6110 (diff) | |
download | linux-stable-7d870936602533836bba821bd5c679c62c52a95f.tar.gz linux-stable-7d870936602533836bba821bd5c679c62c52a95f.tar.bz2 linux-stable-7d870936602533836bba821bd5c679c62c52a95f.zip |
dccp ccid-2: Separate internals of Ack Vectors from option-parsing code
This patch
* separates Ack Vector housekeeping code from option-insertion code;
* shifts option-specific code from ackvec.c into options.c;
* introduces a dedicated routine to take care of the Ack Vector records;
* simplifies the dccp_ackvec_insert_avr() routine: the BUG_ON was redundant,
since the list is automatically arranged in descending order of ack_seqno.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Diffstat (limited to 'net/dccp/options.c')
-rw-r--r-- | net/dccp/options.c | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/net/dccp/options.c b/net/dccp/options.c index 799c6f4547cd..f4ff0a308269 100644 --- a/net/dccp/options.c +++ b/net/dccp/options.c @@ -425,6 +425,66 @@ static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp, return 0; } +static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb) +{ + struct dccp_sock *dp = dccp_sk(sk); + struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec; + /* Figure out how many options do we need to represent the ackvec */ + const u8 nr_opts = DIV_ROUND_UP(av->av_vec_len, DCCP_SINGLE_OPT_MAXLEN); + u16 len = av->av_vec_len + 2 * nr_opts; + u8 i, nonce = 0; + const unsigned char *tail, *from; + unsigned char *to; + + if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) + return -1; + + DCCP_SKB_CB(skb)->dccpd_opt_len += len; + + to = skb_push(skb, len); + len = av->av_vec_len; + from = av->av_buf + av->av_buf_head; + tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN; + + for (i = 0; i < nr_opts; ++i) { + int copylen = len; + + if (len > DCCP_SINGLE_OPT_MAXLEN) + copylen = DCCP_SINGLE_OPT_MAXLEN; + + /* + * RFC 4340, 12.2: Encode the Nonce Echo for this Ack Vector via + * its type; ack_nonce is the sum of all individual buf_nonce's. + */ + nonce ^= av->av_buf_nonce[i]; + + *to++ = DCCPO_ACK_VECTOR_0 + av->av_buf_nonce[i]; + *to++ = copylen + 2; + + /* Check if buf_head wraps */ + if (from + copylen > tail) { + const u16 tailsize = tail - from; + + memcpy(to, from, tailsize); + to += tailsize; + len -= tailsize; + copylen -= tailsize; + from = av->av_buf; + } + + memcpy(to, from, copylen); + from += copylen; + to += copylen; + len -= copylen; + } + /* + * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340. + */ + if (dccp_ackvec_update_records(av, DCCP_SKB_CB(skb)->dccpd_seq, nonce)) + return -ENOBUFS; + return 0; +} + /** * dccp_insert_option_mandatory - Mandatory option (5.8.2) * Note that since we are using skb_push, this function needs to be called |