struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst,
struct request_sock *req)
{
struct dccp_hdr *dh;
struct dccp_request_sock *dreq;
const u32 dccp_header_size = sizeof(struct dccp_hdr) +
sizeof(struct dccp_hdr_ext) +
sizeof(struct dccp_hdr_response);
struct sk_buff *skb;
/* sk is marked const to clearly express we dont hold socket lock.
* sock_wmalloc() will atomically change sk->sk_wmem_alloc,
* it is safe to promote sk to non const.
*/
skb = sock_wmalloc((struct sock *)sk, MAX_DCCP_HEADER, 1,
GFP_ATOMIC);
if (!skb)
return NULL;
skb_reserve(skb, MAX_DCCP_HEADER);
skb_dst_set(skb, dst_clone(dst));
dreq = dccp_rsk(req);
if (inet_rsk(req)->acked) /* increase GSS upon retransmission */
dccp_inc_seqno(&dreq->dreq_gss);
DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_gss;
/* Resolve feature dependencies resulting from choice of CCID */
if (dccp_feat_server_ccid_dependencies(dreq))
goto response_failed;
if (dccp_insert_options_rsk(dreq, skb))
goto response_failed;
/* Build and checksum header */
dh = dccp_zeroed_hdr(skb, dccp_header_size);
dh->dccph_sport = htons(inet_rsk(req)->ir_num);
dh->dccph_dport = inet_rsk(req)->ir_rmt_port;
dh->dccph_doff = (dccp_header_size +
DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
dh->dccph_type = DCCP_PKT_RESPONSE;
dh->dccph_x = 1;
dccp_hdr_set_seq(dh, dreq->dreq_gss);
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_gsr);
dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
dccp_csum_outgoing(skb);
/* We use `acked' to remember that a Response was already sent. */
inet_rsk(req)->acked = 1;
DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
return skb;
response_failed:
kfree_skb(skb);
return NULL;
}
struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
struct request_sock *req)
{
struct dccp_hdr *dh;
struct dccp_request_sock *dreq;
const u32 dccp_header_size = sizeof(struct dccp_hdr) +
sizeof(struct dccp_hdr_ext) +
sizeof(struct dccp_hdr_response);
struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
GFP_ATOMIC);
if (skb == NULL)
return NULL;
/* Reserve space for headers. */
skb_reserve(skb, sk->sk_prot->max_header);
skb_dst_set(skb, dst_clone(dst));
dreq = dccp_rsk(req);
if (inet_rsk(req)->acked) /* increase ISS upon retransmission */
dccp_inc_seqno(&dreq->dreq_iss);
DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
/* Resolve feature dependencies resulting from choice of CCID */
if (dccp_feat_server_ccid_dependencies(dreq))
goto response_failed;
if (dccp_insert_options_rsk(dreq, skb))
goto response_failed;
/* Build and checksum header */
dh = dccp_zeroed_hdr(skb, dccp_header_size);
dh->dccph_sport = inet_rsk(req)->loc_port;
dh->dccph_dport = inet_rsk(req)->rmt_port;
dh->dccph_doff = (dccp_header_size +
DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
dh->dccph_type = DCCP_PKT_RESPONSE;
dh->dccph_x = 1;
dccp_hdr_set_seq(dh, dreq->dreq_iss);
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
dccp_csum_outgoing(skb);
/* We use `acked' to remember that a Response was already sent. */
inet_rsk(req)->acked = 1;
DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
return skb;
response_failed:
kfree_skb(skb);
return NULL;
}
struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
struct request_sock *req)
{
struct dccp_hdr *dh;
struct dccp_request_sock *dreq;
const u32 dccp_header_size = sizeof(struct dccp_hdr) +
sizeof(struct dccp_hdr_ext) +
sizeof(struct dccp_hdr_response);
struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
GFP_ATOMIC);
if (skb == NULL)
return NULL;
skb_reserve(skb, sk->sk_prot->max_header);
skb_dst_set(skb, dst_clone(dst));
dreq = dccp_rsk(req);
if (inet_rsk(req)->acked)
dccp_inc_seqno(&dreq->dreq_iss);
DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
if (dccp_feat_server_ccid_dependencies(dreq))
goto response_failed;
if (dccp_insert_options_rsk(dreq, skb))
goto response_failed;
dh = dccp_zeroed_hdr(skb, dccp_header_size);
dh->dccph_sport = inet_rsk(req)->loc_port;
dh->dccph_dport = inet_rsk(req)->rmt_port;
dh->dccph_doff = (dccp_header_size +
DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
dh->dccph_type = DCCP_PKT_RESPONSE;
dh->dccph_x = 1;
dccp_hdr_set_seq(dh, dreq->dreq_iss);
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
dccp_csum_outgoing(skb);
inet_rsk(req)->acked = 1;
DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
return skb;
response_failed:
kfree_skb(skb);
return NULL;
}
static struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
const enum dccp_reset_codes code)
{
struct dccp_hdr *dh;
struct dccp_sock *dp = dccp_sk(sk);
const u32 dccp_header_size = sizeof(struct dccp_hdr) +
sizeof(struct dccp_hdr_ext) +
sizeof(struct dccp_hdr_reset);
struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
GFP_ATOMIC);
if (skb == NULL)
return NULL;
/* Reserve space for headers. */
skb_reserve(skb, sk->sk_prot->max_header);
skb->dst = dst_clone(dst);
skb->csum = 0;
dccp_inc_seqno(&dp->dccps_gss);
DCCP_SKB_CB(skb)->dccpd_reset_code = code;
DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss;
if (dccp_insert_options(sk, skb)) {
kfree_skb(skb);
return NULL;
}
skb->h.raw = skb_push(skb, dccp_header_size);
dh = dccp_hdr(skb);
memset(dh, 0, dccp_header_size);
dh->dccph_sport = inet_sk(sk)->sport;
dh->dccph_dport = inet_sk(sk)->dport;
dh->dccph_doff = (dccp_header_size +
DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
dh->dccph_type = DCCP_PKT_RESET;
dh->dccph_x = 1;
dccp_hdr_set_seq(dh, dp->dccps_gss);
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
dccp_hdr_reset(skb)->dccph_reset_code = code;
inet_csk(sk)->icsk_af_ops->send_check(sk, skb->len, skb);
DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
return skb;
}
struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
const enum dccp_reset_codes code)
{
struct dccp_hdr *dh;
struct dccp_sock *dp = dccp_sk(sk);
const int dccp_header_size = sizeof(struct dccp_hdr) +
sizeof(struct dccp_hdr_ext) +
sizeof(struct dccp_hdr_reset);
struct sk_buff *skb = sock_wmalloc(sk, MAX_HEADER + DCCP_MAX_OPT_LEN +
dccp_header_size, 1,
GFP_ATOMIC);
if (skb == NULL)
return NULL;
/* Reserve space for headers. */
skb_reserve(skb, MAX_HEADER + DCCP_MAX_OPT_LEN + dccp_header_size);
skb->dst = dst_clone(dst);
skb->csum = 0;
dccp_inc_seqno(&dp->dccps_gss);
DCCP_SKB_CB(skb)->dccpd_reset_code = code;
DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss;
dccp_insert_options(sk, skb);
skb->h.raw = skb_push(skb, dccp_header_size);
dh = dccp_hdr(skb);
memset(dh, 0, dccp_header_size);
dh->dccph_sport = inet_sk(sk)->sport;
dh->dccph_dport = inet_sk(sk)->dport;
dh->dccph_doff = (dccp_header_size +
DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
dh->dccph_type = DCCP_PKT_RESET;
dh->dccph_x = 1;
dccp_hdr_set_seq(dh, dp->dccps_gss);
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
dccp_hdr_reset(skb)->dccph_reset_code = code;
dh->dccph_checksum = dccp_v4_checksum(skb, inet_sk(sk)->saddr,
inet_sk(sk)->daddr);
DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
return skb;
}
/*
* All SKB's seen here are completely headerless. It is our
* job to build the DCCP header, and pass the packet down to
* IP so it can do the same plus pass the packet off to the
* device.
*/
static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
{
if (likely(skb != NULL)) {
const struct inet_sock *inet = inet_sk(sk);
const struct inet_connection_sock *icsk = inet_csk(sk);
struct dccp_sock *dp = dccp_sk(sk);
struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
struct dccp_hdr *dh;
/* XXX For now we're using only 48 bits sequence numbers */
const u32 dccp_header_size = sizeof(*dh) +
sizeof(struct dccp_hdr_ext) +
dccp_packet_hdr_len(dcb->dccpd_type);
int err, set_ack = 1;
u64 ackno = dp->dccps_gsr;
dccp_inc_seqno(&dp->dccps_gss);
switch (dcb->dccpd_type) {
case DCCP_PKT_DATA:
set_ack = 0;
/* fall through */
case DCCP_PKT_DATAACK:
case DCCP_PKT_RESET:
break;
case DCCP_PKT_REQUEST:
set_ack = 0;
/* fall through */
case DCCP_PKT_SYNC:
case DCCP_PKT_SYNCACK:
ackno = dcb->dccpd_ack_seq;
/* fall through */
default:
/*
* Set owner/destructor: some skbs are allocated via
* alloc_skb (e.g. when retransmission may happen).
* Only Data, DataAck, and Reset packets should come
* through here with skb->sk set.
*/
WARN_ON(skb->sk);
skb_set_owner_w(skb, sk);
break;
}
dcb->dccpd_seq = dp->dccps_gss;
if (dccp_insert_options(sk, skb)) {
kfree_skb(skb);
return -EPROTO;
}
/* Build DCCP header and checksum it. */
dh = dccp_zeroed_hdr(skb, dccp_header_size);
dh->dccph_type = dcb->dccpd_type;
dh->dccph_sport = inet->sport;
dh->dccph_dport = inet->dport;
dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4;
dh->dccph_ccval = dcb->dccpd_ccval;
dh->dccph_cscov = dp->dccps_pcslen;
/* XXX For now we're using only 48 bits sequence numbers */
dh->dccph_x = 1;
dp->dccps_awh = dp->dccps_gss;
dccp_hdr_set_seq(dh, dp->dccps_gss);
if (set_ack)
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
switch (dcb->dccpd_type) {
case DCCP_PKT_REQUEST:
dccp_hdr_request(skb)->dccph_req_service =
dp->dccps_service;
break;
case DCCP_PKT_RESET:
dccp_hdr_reset(skb)->dccph_reset_code =
dcb->dccpd_reset_code;
break;
}
icsk->icsk_af_ops->send_check(sk, 0, skb);
if (set_ack)
dccp_event_ack_sent(sk);
DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
err = icsk->icsk_af_ops->queue_xmit(skb, 0);
return net_xmit_eval(err);
}
return -ENOBUFS;
}
static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
{
const struct dccp_hdr *dh = dccp_hdr(skb);
struct dccp_sock *dp = dccp_sk(sk);
u64 lswl, lawl;
/*
* Step 5: Prepare sequence numbers for Sync
* If P.type == Sync or P.type == SyncAck,
* If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
* / * P is valid, so update sequence number variables
* accordingly. After this update, P will pass the tests
* in Step 6. A SyncAck is generated if necessary in
* Step 15 * /
* Update S.GSR, S.SWL, S.SWH
* Otherwise,
* Drop packet and return
*/
if (dh->dccph_type == DCCP_PKT_SYNC ||
dh->dccph_type == DCCP_PKT_SYNCACK) {
if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
dp->dccps_awl, dp->dccps_awh) &&
!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl))
dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
else
return -1;
}
/*
* Step 6: Check sequence numbers
* Let LSWL = S.SWL and LAWL = S.AWL
* If P.type == CloseReq or P.type == Close or P.type == Reset,
* LSWL := S.GSR + 1, LAWL := S.GAR
* If LSWL <= P.seqno <= S.SWH
* and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
* Update S.GSR, S.SWL, S.SWH
* If P.type != Sync,
* Update S.GAR
* Otherwise,
* Send Sync packet acknowledging P.seqno
* Drop packet and return
*/
lswl = dp->dccps_swl;
lawl = dp->dccps_awl;
if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
dh->dccph_type == DCCP_PKT_CLOSE ||
dh->dccph_type == DCCP_PKT_RESET) {
lswl = dp->dccps_gsr;
dccp_inc_seqno(&lswl);
lawl = dp->dccps_gar;
}
if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) &&
(DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ ||
between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
lawl, dp->dccps_awh))) {
dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
if (dh->dccph_type != DCCP_PKT_SYNC &&
(DCCP_SKB_CB(skb)->dccpd_ack_seq !=
DCCP_PKT_WITHOUT_ACK_SEQ))
dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;
} else {
DCCP_WARN("DCCP: Step 6 failed for %s packet, "
"(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
"(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
"sending SYNC...\n", dccp_packet_name(dh->dccph_type),
(unsigned long long) lswl,
(unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq,
(unsigned long long) dp->dccps_swh,
(DCCP_SKB_CB(skb)->dccpd_ack_seq ==
DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists",
(unsigned long long) lawl,
(unsigned long long) DCCP_SKB_CB(skb)->dccpd_ack_seq,
(unsigned long long) dp->dccps_awh);
dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
return -1;
}
return 0;
}
/*
* All SKB's seen here are completely headerless. It is our
* job to build the DCCP header, and pass the packet down to
* IP so it can do the same plus pass the packet off to the
* device.
*/
int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
{
if (likely(skb != NULL)) {
const struct inet_sock *inet = inet_sk(sk);
struct dccp_sock *dp = dccp_sk(sk);
struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
struct dccp_hdr *dh;
/* XXX For now we're using only 48 bits sequence numbers */
const int dccp_header_size = sizeof(*dh) +
sizeof(struct dccp_hdr_ext) +
dccp_packet_hdr_len(dcb->dccpd_type);
int err, set_ack = 1;
u64 ackno = dp->dccps_gsr;
dccp_inc_seqno(&dp->dccps_gss);
switch (dcb->dccpd_type) {
case DCCP_PKT_DATA:
set_ack = 0;
break;
case DCCP_PKT_SYNC:
case DCCP_PKT_SYNCACK:
ackno = dcb->dccpd_seq;
break;
}
dcb->dccpd_seq = dp->dccps_gss;
dccp_insert_options(sk, skb);
skb->h.raw = skb_push(skb, dccp_header_size);
dh = dccp_hdr(skb);
if (!skb->sk)
skb_set_owner_w(skb, sk);
/* Build DCCP header and checksum it. */
memset(dh, 0, dccp_header_size);
dh->dccph_type = dcb->dccpd_type;
dh->dccph_sport = inet->sport;
dh->dccph_dport = inet->dport;
dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4;
dh->dccph_ccval = dcb->dccpd_ccval;
/* XXX For now we're using only 48 bits sequence numbers */
dh->dccph_x = 1;
dp->dccps_awh = dp->dccps_gss;
dccp_hdr_set_seq(dh, dp->dccps_gss);
if (set_ack)
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
switch (dcb->dccpd_type) {
case DCCP_PKT_REQUEST:
dccp_hdr_request(skb)->dccph_req_service =
dp->dccps_service;
break;
case DCCP_PKT_RESET:
dccp_hdr_reset(skb)->dccph_reset_code =
dcb->dccpd_reset_code;
break;
}
dh->dccph_checksum = dccp_v4_checksum(skb, inet->saddr,
inet->daddr);
if (set_ack)
dccp_event_ack_sent(sk);
DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
err = ip_queue_xmit(skb, 0);
if (err <= 0)
return err;
/* NET_XMIT_CN is special. It does not guarantee,
* that this packet is lost. It tells that device
* is about to start to drop packets or already
* drops some packets of the same priority and
* invokes us to send less aggressively.
*/
return err == NET_XMIT_CN ? 0 : err;
}
return -ENOBUFS;
}
