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dccp ccid-2: Separate internals of Ack Vectors from option-parsing code

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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>
This commit is contained in:
Gerrit Renker 2010-11-10 21:21:02 +01:00
parent f17a37c9b8
commit 7d87093660
3 changed files with 79 additions and 83 deletions
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100
net/dccp/ackvec.c
View File

@ -52,99 +52,35 @@ void dccp_ackvec_free(struct dccp_ackvec *av)
}
}
static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,
struct dccp_ackvec_record *avr)
/**
* dccp_ackvec_update_records - Record information about sent Ack Vectors
* @av: Ack Vector records to update
* @seqno: Sequence number of the packet carrying the Ack Vector just sent
* @nonce_sum: The sum of all buffer nonces contained in the Ack Vector
*/
int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seqno, u8 nonce_sum)
{
/*
* AVRs are sorted by seqno. Since we are sending them in order, we
* just add the AVR at the head of the list.
* -sorbo.
*/
if (!list_empty(&av->av_records)) {
const struct dccp_ackvec_record *head =
list_entry(av->av_records.next,
struct dccp_ackvec_record,
avr_node);
BUG_ON(before48(avr->avr_ack_seqno, head->avr_ack_seqno));
}
list_add(&avr->avr_node, &av->av_records);
}
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;
struct dccp_ackvec_record *avr;
if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
return -1;
avr = kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
if (avr == NULL)
return -1;
return -ENOBUFS;
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.
*/
avr->avr_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
avr->avr_ack_seqno = seqno;
avr->avr_ack_ptr = av->av_buf_head;
avr->avr_ack_ackno = av->av_buf_ackno;
avr->avr_ack_nonce = nonce;
avr->avr_ack_nonce = nonce_sum;
avr->avr_ack_runlen = dccp_ackvec_runlen(av->av_buf + av->av_buf_head);
/*
* Since GSS is incremented for each packet, the list is automatically
* arranged in descending order of @ack_seqno.
*/
list_add(&avr->avr_node, &av->av_records);
dccp_ackvec_insert_avr(av, avr);
dccp_pr_debug("%s ACK Vector 0, len=%d, ack_seqno=%llu, "
"ack_ackno=%llu\n",
dccp_role(sk), avr->avr_ack_runlen,
dccp_pr_debug("Added Vector, ack_seqno=%llu, ack_ackno=%llu (rl=%u)\n",
(unsigned long long)avr->avr_ack_seqno,
(unsigned long long)avr->avr_ack_ackno);
(unsigned long long)avr->avr_ack_ackno,
avr->avr_ack_runlen);
return 0;
}

2
net/dccp/ackvec.h
View File

@ -111,7 +111,7 @@ extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
u64 *ackno, const u8 opt,
const u8 *value, const u8 len);
extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
extern int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum);
static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
{

60
net/dccp/options.c
View File

@ -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