dd0fc66fb3
- added typedef unsigned int __nocast gfp_t; - replaced __nocast uses for gfp flags with gfp_t - it gives exactly the same warnings as far as sparse is concerned, doesn't change generated code (from gcc point of view we replaced unsigned int with typedef) and documents what's going on far better. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
420 lines
12 KiB
C
420 lines
12 KiB
C
/*
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* net/dccp/ackvec.c
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*
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* An implementation of the DCCP protocol
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* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; version 2 of the License;
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*/
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#include "ackvec.h"
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#include "dccp.h"
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#include <linux/dccp.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
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int len = av->dccpav_vec_len + 2;
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struct timeval now;
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u32 elapsed_time;
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unsigned char *to, *from;
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dccp_timestamp(sk, &now);
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elapsed_time = timeval_delta(&now, &av->dccpav_time) / 10;
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if (elapsed_time != 0)
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dccp_insert_option_elapsed_time(sk, skb, elapsed_time);
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if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
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return -1;
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/*
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* XXX: now we have just one ack vector sent record, so
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* we have to wait for it to be cleared.
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*
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* Of course this is not acceptable, but this is just for
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* basic testing now.
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*/
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if (av->dccpav_ack_seqno != DCCP_MAX_SEQNO + 1)
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return -1;
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DCCP_SKB_CB(skb)->dccpd_opt_len += len;
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to = skb_push(skb, len);
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*to++ = DCCPO_ACK_VECTOR_0;
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*to++ = len;
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len = av->dccpav_vec_len;
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from = av->dccpav_buf + av->dccpav_buf_head;
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/* Check if buf_head wraps */
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if (av->dccpav_buf_head + len > av->dccpav_vec_len) {
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const u32 tailsize = (av->dccpav_vec_len - av->dccpav_buf_head);
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memcpy(to, from, tailsize);
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to += tailsize;
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len -= tailsize;
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from = av->dccpav_buf;
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}
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memcpy(to, from, len);
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/*
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* From draft-ietf-dccp-spec-11.txt:
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*
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* For each acknowledgement it sends, the HC-Receiver will add an
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* acknowledgement record. ack_seqno will equal the HC-Receiver
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* sequence number it used for the ack packet; ack_ptr will equal
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* buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
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* equal buf_nonce.
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*
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* This implemention uses just one ack record for now.
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*/
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av->dccpav_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
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av->dccpav_ack_ptr = av->dccpav_buf_head;
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av->dccpav_ack_ackno = av->dccpav_buf_ackno;
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av->dccpav_ack_nonce = av->dccpav_buf_nonce;
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av->dccpav_sent_len = av->dccpav_vec_len;
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dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, "
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"ack_ackno=%llu\n",
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debug_prefix, av->dccpav_sent_len,
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(unsigned long long)av->dccpav_ack_seqno,
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(unsigned long long)av->dccpav_ack_ackno);
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return -1;
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}
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struct dccp_ackvec *dccp_ackvec_alloc(const unsigned int len,
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const gfp_t priority)
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{
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struct dccp_ackvec *av = kmalloc(sizeof(*av) + len, priority);
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if (av != NULL) {
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av->dccpav_buf_len = len;
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av->dccpav_buf_head =
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av->dccpav_buf_tail = av->dccpav_buf_len - 1;
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av->dccpav_buf_ackno =
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av->dccpav_ack_ackno = av->dccpav_ack_seqno = ~0LLU;
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av->dccpav_buf_nonce = av->dccpav_buf_nonce = 0;
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av->dccpav_ack_ptr = 0;
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av->dccpav_time.tv_sec = 0;
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av->dccpav_time.tv_usec = 0;
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av->dccpav_sent_len = av->dccpav_vec_len = 0;
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}
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return av;
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}
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void dccp_ackvec_free(struct dccp_ackvec *av)
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{
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kfree(av);
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}
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static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av,
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const unsigned int index)
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{
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return av->dccpav_buf[index] & DCCP_ACKVEC_STATE_MASK;
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}
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static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av,
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const unsigned int index)
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{
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return av->dccpav_buf[index] & DCCP_ACKVEC_LEN_MASK;
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}
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/*
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* If several packets are missing, the HC-Receiver may prefer to enter multiple
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* bytes with run length 0, rather than a single byte with a larger run length;
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* this simplifies table updates if one of the missing packets arrives.
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*/
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static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av,
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const unsigned int packets,
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const unsigned char state)
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{
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unsigned int gap;
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signed long new_head;
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if (av->dccpav_vec_len + packets > av->dccpav_buf_len)
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return -ENOBUFS;
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gap = packets - 1;
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new_head = av->dccpav_buf_head - packets;
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if (new_head < 0) {
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if (gap > 0) {
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memset(av->dccpav_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED,
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gap + new_head + 1);
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gap = -new_head;
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}
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new_head += av->dccpav_buf_len;
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}
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av->dccpav_buf_head = new_head;
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if (gap > 0)
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memset(av->dccpav_buf + av->dccpav_buf_head + 1,
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DCCP_ACKVEC_STATE_NOT_RECEIVED, gap);
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av->dccpav_buf[av->dccpav_buf_head] = state;
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av->dccpav_vec_len += packets;
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return 0;
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}
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/*
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* Implements the draft-ietf-dccp-spec-11.txt Appendix A
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*/
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int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
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const u64 ackno, const u8 state)
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{
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/*
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* Check at the right places if the buffer is full, if it is, tell the
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* caller to start dropping packets till the HC-Sender acks our ACK
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* vectors, when we will free up space in dccpav_buf.
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*
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* We may well decide to do buffer compression, etc, but for now lets
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* just drop.
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*
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* From Appendix A:
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*
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* Of course, the circular buffer may overflow, either when the
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* HC-Sender is sending data at a very high rate, when the
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* HC-Receiver's acknowledgements are not reaching the HC-Sender,
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* or when the HC-Sender is forgetting to acknowledge those acks
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* (so the HC-Receiver is unable to clean up old state). In this
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* case, the HC-Receiver should either compress the buffer (by
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* increasing run lengths when possible), transfer its state to
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* a larger buffer, or, as a last resort, drop all received
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* packets, without processing them whatsoever, until its buffer
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* shrinks again.
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*/
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/* See if this is the first ackno being inserted */
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if (av->dccpav_vec_len == 0) {
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av->dccpav_buf[av->dccpav_buf_head] = state;
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av->dccpav_vec_len = 1;
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} else if (after48(ackno, av->dccpav_buf_ackno)) {
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const u64 delta = dccp_delta_seqno(av->dccpav_buf_ackno,
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ackno);
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/*
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* Look if the state of this packet is the same as the
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* previous ackno and if so if we can bump the head len.
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*/
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if (delta == 1 &&
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dccp_ackvec_state(av, av->dccpav_buf_head) == state &&
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(dccp_ackvec_len(av, av->dccpav_buf_head) <
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DCCP_ACKVEC_LEN_MASK))
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av->dccpav_buf[av->dccpav_buf_head]++;
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else if (dccp_ackvec_set_buf_head_state(av, delta, state))
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return -ENOBUFS;
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} else {
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/*
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* A.1.2. Old Packets
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*
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* When a packet with Sequence Number S arrives, and
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* S <= buf_ackno, the HC-Receiver will scan the table
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* for the byte corresponding to S. (Indexing structures
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* could reduce the complexity of this scan.)
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*/
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u64 delta = dccp_delta_seqno(ackno, av->dccpav_buf_ackno);
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unsigned int index = av->dccpav_buf_head;
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while (1) {
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const u8 len = dccp_ackvec_len(av, index);
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const u8 state = dccp_ackvec_state(av, index);
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/*
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* valid packets not yet in dccpav_buf have a reserved
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* entry, with a len equal to 0.
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*/
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if (state == DCCP_ACKVEC_STATE_NOT_RECEIVED &&
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len == 0 && delta == 0) { /* Found our
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reserved seat! */
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dccp_pr_debug("Found %llu reserved seat!\n",
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(unsigned long long)ackno);
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av->dccpav_buf[index] = state;
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goto out;
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}
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/* len == 0 means one packet */
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if (delta < len + 1)
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goto out_duplicate;
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delta -= len + 1;
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if (++index == av->dccpav_buf_len)
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index = 0;
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}
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}
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av->dccpav_buf_ackno = ackno;
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dccp_timestamp(sk, &av->dccpav_time);
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out:
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dccp_pr_debug("");
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return 0;
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out_duplicate:
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/* Duplicate packet */
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dccp_pr_debug("Received a dup or already considered lost "
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"packet: %llu\n", (unsigned long long)ackno);
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return -EILSEQ;
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}
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#ifdef CONFIG_IP_DCCP_DEBUG
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void dccp_ackvector_print(const u64 ackno, const unsigned char *vector, int len)
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{
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if (!dccp_debug)
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return;
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printk("ACK vector len=%d, ackno=%llu |", len,
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(unsigned long long)ackno);
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while (len--) {
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const u8 state = (*vector & DCCP_ACKVEC_STATE_MASK) >> 6;
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const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
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printk("%d,%d|", state, rl);
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++vector;
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}
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printk("\n");
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}
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void dccp_ackvec_print(const struct dccp_ackvec *av)
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{
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dccp_ackvector_print(av->dccpav_buf_ackno,
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av->dccpav_buf + av->dccpav_buf_head,
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av->dccpav_vec_len);
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}
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#endif
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static void dccp_ackvec_trow_away_ack_record(struct dccp_ackvec *av)
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{
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/*
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* As we're keeping track of the ack vector size (dccpav_vec_len) and
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* the sent ack vector size (dccpav_sent_len) we don't need
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* dccpav_buf_tail at all, but keep this code here as in the future
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* we'll implement a vector of ack records, as suggested in
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* draft-ietf-dccp-spec-11.txt Appendix A. -acme
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*/
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#if 0
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av->dccpav_buf_tail = av->dccpav_ack_ptr + 1;
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if (av->dccpav_buf_tail >= av->dccpav_vec_len)
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av->dccpav_buf_tail -= av->dccpav_vec_len;
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#endif
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av->dccpav_vec_len -= av->dccpav_sent_len;
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}
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void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk,
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const u64 ackno)
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{
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/* Check if we actually sent an ACK vector */
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if (av->dccpav_ack_seqno == DCCP_MAX_SEQNO + 1)
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return;
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if (ackno == av->dccpav_ack_seqno) {
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#ifdef CONFIG_IP_DCCP_DEBUG
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struct dccp_sock *dp = dccp_sk(sk);
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const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
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"CLIENT rx ack: " : "server rx ack: ";
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#endif
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dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, "
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"ack_ackno=%llu, ACKED!\n",
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debug_prefix, 1,
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(unsigned long long)av->dccpav_ack_seqno,
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(unsigned long long)av->dccpav_ack_ackno);
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dccp_ackvec_trow_away_ack_record(av);
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av->dccpav_ack_seqno = DCCP_MAX_SEQNO + 1;
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}
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}
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static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
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struct sock *sk, u64 ackno,
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const unsigned char len,
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const unsigned char *vector)
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{
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unsigned char i;
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/* Check if we actually sent an ACK vector */
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if (av->dccpav_ack_seqno == DCCP_MAX_SEQNO + 1)
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return;
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/*
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* We're in the receiver half connection, so if the received an ACK
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* vector ackno (e.g. 50) before dccpav_ack_seqno (e.g. 52), we're
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* not interested.
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*
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* Extra explanation with example:
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*
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* if we received an ACK vector with ackno 50, it can only be acking
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* 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent).
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*/
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/* dccp_pr_debug("is %llu < %llu? ", ackno, av->dccpav_ack_seqno); */
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if (before48(ackno, av->dccpav_ack_seqno)) {
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/* dccp_pr_debug_cat("yes\n"); */
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return;
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}
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/* dccp_pr_debug_cat("no\n"); */
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i = len;
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while (i--) {
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const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
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u64 ackno_end_rl;
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dccp_set_seqno(&ackno_end_rl, ackno - rl);
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/*
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* dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl,
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* av->dccpav_ack_seqno, ackno);
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*/
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if (between48(av->dccpav_ack_seqno, ackno_end_rl, ackno)) {
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const u8 state = (*vector &
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DCCP_ACKVEC_STATE_MASK) >> 6;
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/* dccp_pr_debug_cat("yes\n"); */
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if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) {
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#ifdef CONFIG_IP_DCCP_DEBUG
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struct dccp_sock *dp = dccp_sk(sk);
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const char *debug_prefix =
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dp->dccps_role == DCCP_ROLE_CLIENT ?
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"CLIENT rx ack: " : "server rx ack: ";
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#endif
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dccp_pr_debug("%sACK vector 0, len=%d, "
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"ack_seqno=%llu, ack_ackno=%llu, "
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"ACKED!\n",
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debug_prefix, len,
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(unsigned long long)
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av->dccpav_ack_seqno,
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(unsigned long long)
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av->dccpav_ack_ackno);
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dccp_ackvec_trow_away_ack_record(av);
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}
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/*
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* If dccpav_ack_seqno was not received, no problem
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* we'll send another ACK vector.
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*/
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av->dccpav_ack_seqno = DCCP_MAX_SEQNO + 1;
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break;
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}
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/* dccp_pr_debug_cat("no\n"); */
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dccp_set_seqno(&ackno, ackno_end_rl - 1);
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++vector;
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}
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}
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int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
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const u8 opt, const u8 *value, const u8 len)
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{
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if (len > DCCP_MAX_ACKVEC_LEN)
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return -1;
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/* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */
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dccp_ackvec_check_rcv_ackvector(dccp_sk(sk)->dccps_hc_rx_ackvec, sk,
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DCCP_SKB_CB(skb)->dccpd_ack_seq,
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len, value);
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return 0;
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}
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