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[DCCP]: Debug timeval operations
Problem: Most target types in the CCID3 code are u32, so subtle conversion errors can occur if signed time calculations yield negative results: the original values are lost in the conversion to unsigned, calculation errors go undetected. This patch therefore * sets all critical time types from unsigned to suseconds_t * avoids comparison between signed/unsigned via type-casting * provides ample warning messages in case time calculations are negative These warning messages can be removed at a later stage when the code has undergone more testing. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This commit is contained in:
Gerrit Renker
David S. Miller
parent
bfe24a6cc2
commit
0f9e5b573f
@ -128,8 +128,8 @@ static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
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hctx->ccid3hctx_x = max_t(u64, hctx->ccid3hctx_x,
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(hctx->ccid3hctx_s << 6)/TFRC_T_MBI);
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} else if (timeval_delta(now, &hctx->ccid3hctx_t_ld) >=
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hctx->ccid3hctx_rtt) {
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} else if (timeval_delta(now, &hctx->ccid3hctx_t_ld) -
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(suseconds_t)hctx->ccid3hctx_rtt >= 0 ) {
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hctx->ccid3hctx_x = max(2 * min(hctx->ccid3hctx_x,
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hctx->ccid3hctx_x_recv),
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@ -271,7 +271,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
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struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
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struct dccp_tx_hist_entry *new_packet;
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struct timeval now;
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long delay;
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suseconds_t delay;
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BUG_ON(hctx == NULL);
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@ -331,7 +331,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
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* else
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* // send the packet in (t_nom - t_now) milliseconds.
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*/
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if (delay - (long)hctx->ccid3hctx_delta >= 0)
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if (delay - (suseconds_t)hctx->ccid3hctx_delta >= 0)
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return delay / 1000L;
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break;
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case TFRC_SSTATE_TERM:
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@ -353,7 +353,7 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
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const struct dccp_sock *dp = dccp_sk(sk);
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struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
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struct timeval now;
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unsigned long quarter_rtt;
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suseconds_t quarter_rtt;
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struct dccp_tx_hist_entry *packet;
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BUG_ON(hctx == NULL);
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@ -450,10 +450,8 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
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r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
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t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
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if (unlikely(r_sample <= 0)) {
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DCCP_WARN("WARNING: R_sample (%ld) <= 0!\n", r_sample);
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r_sample = 0;
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} else if (unlikely(r_sample <= t_elapsed))
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DCCP_BUG_ON(r_sample < 0);
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if (unlikely(r_sample <= t_elapsed))
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DCCP_WARN("WARNING: r_sample=%ldus <= t_elapsed=%ldus\n",
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r_sample, t_elapsed);
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else
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@ -698,6 +696,7 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk)
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struct dccp_sock *dp = dccp_sk(sk);
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struct dccp_rx_hist_entry *packet;
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struct timeval now;
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suseconds_t delta;
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ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
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@ -707,12 +706,12 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk)
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case TFRC_RSTATE_NO_DATA:
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hcrx->ccid3hcrx_x_recv = 0;
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break;
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case TFRC_RSTATE_DATA: {
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const u32 delta = timeval_delta(&now,
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&hcrx->ccid3hcrx_tstamp_last_feedback);
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case TFRC_RSTATE_DATA:
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delta = timeval_delta(&now,
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&hcrx->ccid3hcrx_tstamp_last_feedback);
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DCCP_BUG_ON(delta < 0);
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hcrx->ccid3hcrx_x_recv =
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scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
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}
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break;
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case TFRC_RSTATE_TERM:
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DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
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@ -730,9 +729,10 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk)
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hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
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hcrx->ccid3hcrx_bytes_recv = 0;
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/* Convert to multiples of 10us */
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hcrx->ccid3hcrx_elapsed_time =
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timeval_delta(&now, &packet->dccphrx_tstamp) / 10;
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/* Elapsed time information [RFC 4340, 13.2] in units of 10 * usecs */
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delta = timeval_delta(&now, &packet->dccphrx_tstamp);
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DCCP_BUG_ON(delta < 0);
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hcrx->ccid3hcrx_elapsed_time = delta / 10;
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if (hcrx->ccid3hcrx_p == 0)
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hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
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@ -785,7 +785,8 @@ static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
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{
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struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
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struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
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u32 rtt, delta, x_recv, p;
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u32 x_recv, p;
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suseconds_t rtt, delta;
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struct timeval tstamp = { 0, };
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int interval = 0;
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int win_count = 0;
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@ -830,8 +831,12 @@ found:
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DCCP_CRIT("tail is null\n");
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return ~0;
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}
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rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval;
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ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n",
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delta = timeval_delta(&tstamp, &tail->dccphrx_tstamp);
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DCCP_BUG_ON(delta < 0);
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rtt = delta * 4 / interval;
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ccid3_pr_debug("%s, sk=%p, approximated RTT to %ldus\n",
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dccp_role(sk), sk, rtt);
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/*
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@ -849,8 +854,9 @@ found:
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dccp_timestamp(sk, &tstamp);
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delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
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x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
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DCCP_BUG_ON(delta <= 0);
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x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
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if (x_recv == 0) { /* would also trigger divide-by-zero */
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DCCP_WARN("X_recv==0\n");
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if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) {
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@ -977,7 +983,8 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
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const struct dccp_options_received *opt_recv;
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struct dccp_rx_hist_entry *packet;
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struct timeval now;
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u32 p_prev, rtt_prev, r_sample, t_elapsed;
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u32 p_prev, rtt_prev;
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suseconds_t r_sample, t_elapsed;
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int loss, payload_size;
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BUG_ON(hcrx == NULL);
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@ -997,8 +1004,9 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
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r_sample = timeval_usecs(&now);
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t_elapsed = opt_recv->dccpor_elapsed_time * 10;
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DCCP_BUG_ON(r_sample < 0);
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if (unlikely(r_sample <= t_elapsed))
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DCCP_WARN("r_sample=%uus, t_elapsed=%uus\n",
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DCCP_WARN("r_sample=%ldus, t_elapsed=%ldus\n",
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r_sample, t_elapsed);
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else
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r_sample -= t_elapsed;
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@ -1051,8 +1059,8 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
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break;
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dccp_timestamp(sk, &now);
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if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >=
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hcrx->ccid3hcrx_rtt) {
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if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) -
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(suseconds_t)hcrx->ccid3hcrx_rtt >= 0) {
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hcrx->ccid3hcrx_tstamp_last_ack = now;
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ccid3_hc_rx_send_feedback(sk);
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}
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@ -432,6 +432,7 @@ static inline void timeval_sub_usecs(struct timeval *tv,
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tv->tv_sec--;
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tv->tv_usec += USEC_PER_SEC;
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}
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DCCP_BUG_ON(tv->tv_sec < 0);
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}
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#ifdef CONFIG_SYSCTL
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