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![Eric Dumazet](/assets/img/avatar_default.png)
iproute2 package is well behaved, but malicious user space can
provide illegal shift values and trigger UBSAN reports.
Add stab parameter to red_check_params() to validate user input.
syzbot reported:
UBSAN: shift-out-of-bounds in ./include/net/red.h:312:18
shift exponent 111 is too large for 64-bit type 'long unsigned int'
CPU: 1 PID: 14662 Comm: syz-executor.3 Not tainted 5.12.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
__ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:327
red_calc_qavg_from_idle_time include/net/red.h:312 [inline]
red_calc_qavg include/net/red.h:353 [inline]
choke_enqueue.cold+0x18/0x3dd net/sched/sch_choke.c:221
__dev_xmit_skb net/core/dev.c:3837 [inline]
__dev_queue_xmit+0x1943/0x2e00 net/core/dev.c:4150
neigh_hh_output include/net/neighbour.h:499 [inline]
neigh_output include/net/neighbour.h:508 [inline]
ip6_finish_output2+0x911/0x1700 net/ipv6/ip6_output.c:117
__ip6_finish_output net/ipv6/ip6_output.c:182 [inline]
__ip6_finish_output+0x4c1/0xe10 net/ipv6/ip6_output.c:161
ip6_finish_output+0x35/0x200 net/ipv6/ip6_output.c:192
NF_HOOK_COND include/linux/netfilter.h:290 [inline]
ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:215
dst_output include/net/dst.h:448 [inline]
NF_HOOK include/linux/netfilter.h:301 [inline]
NF_HOOK include/linux/netfilter.h:295 [inline]
ip6_xmit+0x127e/0x1eb0 net/ipv6/ip6_output.c:320
inet6_csk_xmit+0x358/0x630 net/ipv6/inet6_connection_sock.c:135
dccp_transmit_skb+0x973/0x12c0 net/dccp/output.c:138
dccp_send_reset+0x21b/0x2b0 net/dccp/output.c:535
dccp_finish_passive_close net/dccp/proto.c:123 [inline]
dccp_finish_passive_close+0xed/0x140 net/dccp/proto.c:118
dccp_terminate_connection net/dccp/proto.c:958 [inline]
dccp_close+0xb3c/0xe60 net/dccp/proto.c:1028
inet_release+0x12e/0x280 net/ipv4/af_inet.c:431
inet6_release+0x4c/0x70 net/ipv6/af_inet6.c:478
__sock_release+0xcd/0x280 net/socket.c:599
sock_close+0x18/0x20 net/socket.c:1258
__fput+0x288/0x920 fs/file_table.c:280
task_work_run+0xdd/0x1a0 kernel/task_work.c:140
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
Fixes: 8afa10cbe2
("net_sched: red: Avoid illegal values")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
519 lines
12 KiB
C
519 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* net/sched/sch_choke.c CHOKE scheduler
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*
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* Copyright (c) 2011 Stephen Hemminger <shemminger@vyatta.com>
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* Copyright (c) 2011 Eric Dumazet <eric.dumazet@gmail.com>
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <linux/vmalloc.h>
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#include <net/pkt_sched.h>
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#include <net/pkt_cls.h>
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#include <net/inet_ecn.h>
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#include <net/red.h>
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#include <net/flow_dissector.h>
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/*
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CHOKe stateless AQM for fair bandwidth allocation
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=================================================
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CHOKe (CHOose and Keep for responsive flows, CHOose and Kill for
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unresponsive flows) is a variant of RED that penalizes misbehaving flows but
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maintains no flow state. The difference from RED is an additional step
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during the enqueuing process. If average queue size is over the
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low threshold (qmin), a packet is chosen at random from the queue.
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If both the new and chosen packet are from the same flow, both
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are dropped. Unlike RED, CHOKe is not really a "classful" qdisc because it
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needs to access packets in queue randomly. It has a minimal class
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interface to allow overriding the builtin flow classifier with
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filters.
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Source:
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R. Pan, B. Prabhakar, and K. Psounis, "CHOKe, A Stateless
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Active Queue Management Scheme for Approximating Fair Bandwidth Allocation",
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IEEE INFOCOM, 2000.
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A. Tang, J. Wang, S. Low, "Understanding CHOKe: Throughput and Spatial
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Characteristics", IEEE/ACM Transactions on Networking, 2004
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*/
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/* Upper bound on size of sk_buff table (packets) */
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#define CHOKE_MAX_QUEUE (128*1024 - 1)
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struct choke_sched_data {
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/* Parameters */
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u32 limit;
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unsigned char flags;
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struct red_parms parms;
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/* Variables */
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struct red_vars vars;
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struct {
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u32 prob_drop; /* Early probability drops */
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u32 prob_mark; /* Early probability marks */
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u32 forced_drop; /* Forced drops, qavg > max_thresh */
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u32 forced_mark; /* Forced marks, qavg > max_thresh */
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u32 pdrop; /* Drops due to queue limits */
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u32 other; /* Drops due to drop() calls */
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u32 matched; /* Drops to flow match */
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} stats;
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unsigned int head;
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unsigned int tail;
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unsigned int tab_mask; /* size - 1 */
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struct sk_buff **tab;
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};
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/* number of elements in queue including holes */
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static unsigned int choke_len(const struct choke_sched_data *q)
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{
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return (q->tail - q->head) & q->tab_mask;
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}
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/* Is ECN parameter configured */
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static int use_ecn(const struct choke_sched_data *q)
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{
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return q->flags & TC_RED_ECN;
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}
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/* Should packets over max just be dropped (versus marked) */
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static int use_harddrop(const struct choke_sched_data *q)
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{
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return q->flags & TC_RED_HARDDROP;
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}
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/* Move head pointer forward to skip over holes */
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static void choke_zap_head_holes(struct choke_sched_data *q)
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{
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do {
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q->head = (q->head + 1) & q->tab_mask;
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if (q->head == q->tail)
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break;
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} while (q->tab[q->head] == NULL);
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}
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/* Move tail pointer backwards to reuse holes */
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static void choke_zap_tail_holes(struct choke_sched_data *q)
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{
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do {
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q->tail = (q->tail - 1) & q->tab_mask;
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if (q->head == q->tail)
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break;
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} while (q->tab[q->tail] == NULL);
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}
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/* Drop packet from queue array by creating a "hole" */
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static void choke_drop_by_idx(struct Qdisc *sch, unsigned int idx,
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struct sk_buff **to_free)
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{
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struct choke_sched_data *q = qdisc_priv(sch);
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struct sk_buff *skb = q->tab[idx];
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q->tab[idx] = NULL;
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if (idx == q->head)
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choke_zap_head_holes(q);
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if (idx == q->tail)
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choke_zap_tail_holes(q);
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qdisc_qstats_backlog_dec(sch, skb);
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qdisc_tree_reduce_backlog(sch, 1, qdisc_pkt_len(skb));
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qdisc_drop(skb, sch, to_free);
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--sch->q.qlen;
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}
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struct choke_skb_cb {
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u8 keys_valid;
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struct flow_keys_digest keys;
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};
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static inline struct choke_skb_cb *choke_skb_cb(const struct sk_buff *skb)
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{
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qdisc_cb_private_validate(skb, sizeof(struct choke_skb_cb));
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return (struct choke_skb_cb *)qdisc_skb_cb(skb)->data;
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}
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/*
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* Compare flow of two packets
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* Returns true only if source and destination address and port match.
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* false for special cases
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*/
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static bool choke_match_flow(struct sk_buff *skb1,
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struct sk_buff *skb2)
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{
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struct flow_keys temp;
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if (skb1->protocol != skb2->protocol)
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return false;
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if (!choke_skb_cb(skb1)->keys_valid) {
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choke_skb_cb(skb1)->keys_valid = 1;
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skb_flow_dissect_flow_keys(skb1, &temp, 0);
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make_flow_keys_digest(&choke_skb_cb(skb1)->keys, &temp);
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}
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if (!choke_skb_cb(skb2)->keys_valid) {
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choke_skb_cb(skb2)->keys_valid = 1;
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skb_flow_dissect_flow_keys(skb2, &temp, 0);
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make_flow_keys_digest(&choke_skb_cb(skb2)->keys, &temp);
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}
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return !memcmp(&choke_skb_cb(skb1)->keys,
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&choke_skb_cb(skb2)->keys,
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sizeof(choke_skb_cb(skb1)->keys));
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}
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/*
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* Select a packet at random from queue
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* HACK: since queue can have holes from previous deletion; retry several
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* times to find a random skb but then just give up and return the head
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* Will return NULL if queue is empty (q->head == q->tail)
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*/
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static struct sk_buff *choke_peek_random(const struct choke_sched_data *q,
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unsigned int *pidx)
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{
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struct sk_buff *skb;
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int retrys = 3;
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do {
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*pidx = (q->head + prandom_u32_max(choke_len(q))) & q->tab_mask;
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skb = q->tab[*pidx];
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if (skb)
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return skb;
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} while (--retrys > 0);
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return q->tab[*pidx = q->head];
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}
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/*
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* Compare new packet with random packet in queue
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* returns true if matched and sets *pidx
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*/
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static bool choke_match_random(const struct choke_sched_data *q,
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struct sk_buff *nskb,
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unsigned int *pidx)
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{
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struct sk_buff *oskb;
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if (q->head == q->tail)
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return false;
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oskb = choke_peek_random(q, pidx);
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return choke_match_flow(oskb, nskb);
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}
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static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch,
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struct sk_buff **to_free)
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{
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struct choke_sched_data *q = qdisc_priv(sch);
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const struct red_parms *p = &q->parms;
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choke_skb_cb(skb)->keys_valid = 0;
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/* Compute average queue usage (see RED) */
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q->vars.qavg = red_calc_qavg(p, &q->vars, sch->q.qlen);
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if (red_is_idling(&q->vars))
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red_end_of_idle_period(&q->vars);
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/* Is queue small? */
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if (q->vars.qavg <= p->qth_min)
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q->vars.qcount = -1;
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else {
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unsigned int idx;
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/* Draw a packet at random from queue and compare flow */
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if (choke_match_random(q, skb, &idx)) {
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q->stats.matched++;
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choke_drop_by_idx(sch, idx, to_free);
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goto congestion_drop;
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}
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/* Queue is large, always mark/drop */
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if (q->vars.qavg > p->qth_max) {
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q->vars.qcount = -1;
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qdisc_qstats_overlimit(sch);
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if (use_harddrop(q) || !use_ecn(q) ||
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!INET_ECN_set_ce(skb)) {
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q->stats.forced_drop++;
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goto congestion_drop;
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}
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q->stats.forced_mark++;
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} else if (++q->vars.qcount) {
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if (red_mark_probability(p, &q->vars, q->vars.qavg)) {
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q->vars.qcount = 0;
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q->vars.qR = red_random(p);
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qdisc_qstats_overlimit(sch);
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if (!use_ecn(q) || !INET_ECN_set_ce(skb)) {
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q->stats.prob_drop++;
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goto congestion_drop;
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}
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q->stats.prob_mark++;
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}
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} else
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q->vars.qR = red_random(p);
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}
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/* Admit new packet */
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if (sch->q.qlen < q->limit) {
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q->tab[q->tail] = skb;
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q->tail = (q->tail + 1) & q->tab_mask;
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++sch->q.qlen;
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qdisc_qstats_backlog_inc(sch, skb);
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return NET_XMIT_SUCCESS;
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}
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q->stats.pdrop++;
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return qdisc_drop(skb, sch, to_free);
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congestion_drop:
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qdisc_drop(skb, sch, to_free);
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return NET_XMIT_CN;
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}
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static struct sk_buff *choke_dequeue(struct Qdisc *sch)
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{
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struct choke_sched_data *q = qdisc_priv(sch);
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struct sk_buff *skb;
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if (q->head == q->tail) {
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if (!red_is_idling(&q->vars))
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red_start_of_idle_period(&q->vars);
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return NULL;
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}
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skb = q->tab[q->head];
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q->tab[q->head] = NULL;
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choke_zap_head_holes(q);
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--sch->q.qlen;
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qdisc_qstats_backlog_dec(sch, skb);
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qdisc_bstats_update(sch, skb);
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return skb;
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}
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static void choke_reset(struct Qdisc *sch)
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{
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struct choke_sched_data *q = qdisc_priv(sch);
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while (q->head != q->tail) {
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struct sk_buff *skb = q->tab[q->head];
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q->head = (q->head + 1) & q->tab_mask;
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if (!skb)
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continue;
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rtnl_qdisc_drop(skb, sch);
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}
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sch->q.qlen = 0;
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sch->qstats.backlog = 0;
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if (q->tab)
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memset(q->tab, 0, (q->tab_mask + 1) * sizeof(struct sk_buff *));
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q->head = q->tail = 0;
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red_restart(&q->vars);
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}
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static const struct nla_policy choke_policy[TCA_CHOKE_MAX + 1] = {
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[TCA_CHOKE_PARMS] = { .len = sizeof(struct tc_red_qopt) },
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[TCA_CHOKE_STAB] = { .len = RED_STAB_SIZE },
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[TCA_CHOKE_MAX_P] = { .type = NLA_U32 },
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};
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static void choke_free(void *addr)
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{
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kvfree(addr);
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}
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static int choke_change(struct Qdisc *sch, struct nlattr *opt,
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struct netlink_ext_ack *extack)
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{
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struct choke_sched_data *q = qdisc_priv(sch);
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struct nlattr *tb[TCA_CHOKE_MAX + 1];
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const struct tc_red_qopt *ctl;
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int err;
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struct sk_buff **old = NULL;
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unsigned int mask;
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u32 max_P;
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u8 *stab;
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if (opt == NULL)
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return -EINVAL;
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err = nla_parse_nested_deprecated(tb, TCA_CHOKE_MAX, opt,
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choke_policy, NULL);
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if (err < 0)
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return err;
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if (tb[TCA_CHOKE_PARMS] == NULL ||
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tb[TCA_CHOKE_STAB] == NULL)
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return -EINVAL;
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max_P = tb[TCA_CHOKE_MAX_P] ? nla_get_u32(tb[TCA_CHOKE_MAX_P]) : 0;
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ctl = nla_data(tb[TCA_CHOKE_PARMS]);
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stab = nla_data(tb[TCA_CHOKE_STAB]);
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if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Scell_log, stab))
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return -EINVAL;
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if (ctl->limit > CHOKE_MAX_QUEUE)
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return -EINVAL;
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mask = roundup_pow_of_two(ctl->limit + 1) - 1;
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if (mask != q->tab_mask) {
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struct sk_buff **ntab;
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ntab = kvcalloc(mask + 1, sizeof(struct sk_buff *), GFP_KERNEL);
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if (!ntab)
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return -ENOMEM;
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sch_tree_lock(sch);
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old = q->tab;
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if (old) {
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unsigned int oqlen = sch->q.qlen, tail = 0;
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unsigned dropped = 0;
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while (q->head != q->tail) {
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struct sk_buff *skb = q->tab[q->head];
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q->head = (q->head + 1) & q->tab_mask;
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if (!skb)
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continue;
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if (tail < mask) {
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ntab[tail++] = skb;
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continue;
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}
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dropped += qdisc_pkt_len(skb);
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qdisc_qstats_backlog_dec(sch, skb);
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--sch->q.qlen;
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rtnl_qdisc_drop(skb, sch);
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}
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qdisc_tree_reduce_backlog(sch, oqlen - sch->q.qlen, dropped);
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q->head = 0;
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q->tail = tail;
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}
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q->tab_mask = mask;
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q->tab = ntab;
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} else
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sch_tree_lock(sch);
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q->flags = ctl->flags;
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q->limit = ctl->limit;
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red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog,
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ctl->Plog, ctl->Scell_log,
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stab,
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max_P);
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red_set_vars(&q->vars);
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if (q->head == q->tail)
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red_end_of_idle_period(&q->vars);
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sch_tree_unlock(sch);
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choke_free(old);
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return 0;
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}
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static int choke_init(struct Qdisc *sch, struct nlattr *opt,
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struct netlink_ext_ack *extack)
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{
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return choke_change(sch, opt, extack);
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}
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static int choke_dump(struct Qdisc *sch, struct sk_buff *skb)
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{
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struct choke_sched_data *q = qdisc_priv(sch);
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struct nlattr *opts = NULL;
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struct tc_red_qopt opt = {
|
|
.limit = q->limit,
|
|
.flags = q->flags,
|
|
.qth_min = q->parms.qth_min >> q->parms.Wlog,
|
|
.qth_max = q->parms.qth_max >> q->parms.Wlog,
|
|
.Wlog = q->parms.Wlog,
|
|
.Plog = q->parms.Plog,
|
|
.Scell_log = q->parms.Scell_log,
|
|
};
|
|
|
|
opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
|
|
if (opts == NULL)
|
|
goto nla_put_failure;
|
|
|
|
if (nla_put(skb, TCA_CHOKE_PARMS, sizeof(opt), &opt) ||
|
|
nla_put_u32(skb, TCA_CHOKE_MAX_P, q->parms.max_P))
|
|
goto nla_put_failure;
|
|
return nla_nest_end(skb, opts);
|
|
|
|
nla_put_failure:
|
|
nla_nest_cancel(skb, opts);
|
|
return -EMSGSIZE;
|
|
}
|
|
|
|
static int choke_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
|
|
{
|
|
struct choke_sched_data *q = qdisc_priv(sch);
|
|
struct tc_choke_xstats st = {
|
|
.early = q->stats.prob_drop + q->stats.forced_drop,
|
|
.marked = q->stats.prob_mark + q->stats.forced_mark,
|
|
.pdrop = q->stats.pdrop,
|
|
.other = q->stats.other,
|
|
.matched = q->stats.matched,
|
|
};
|
|
|
|
return gnet_stats_copy_app(d, &st, sizeof(st));
|
|
}
|
|
|
|
static void choke_destroy(struct Qdisc *sch)
|
|
{
|
|
struct choke_sched_data *q = qdisc_priv(sch);
|
|
|
|
choke_free(q->tab);
|
|
}
|
|
|
|
static struct sk_buff *choke_peek_head(struct Qdisc *sch)
|
|
{
|
|
struct choke_sched_data *q = qdisc_priv(sch);
|
|
|
|
return (q->head != q->tail) ? q->tab[q->head] : NULL;
|
|
}
|
|
|
|
static struct Qdisc_ops choke_qdisc_ops __read_mostly = {
|
|
.id = "choke",
|
|
.priv_size = sizeof(struct choke_sched_data),
|
|
|
|
.enqueue = choke_enqueue,
|
|
.dequeue = choke_dequeue,
|
|
.peek = choke_peek_head,
|
|
.init = choke_init,
|
|
.destroy = choke_destroy,
|
|
.reset = choke_reset,
|
|
.change = choke_change,
|
|
.dump = choke_dump,
|
|
.dump_stats = choke_dump_stats,
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
static int __init choke_module_init(void)
|
|
{
|
|
return register_qdisc(&choke_qdisc_ops);
|
|
}
|
|
|
|
static void __exit choke_module_exit(void)
|
|
{
|
|
unregister_qdisc(&choke_qdisc_ops);
|
|
}
|
|
|
|
module_init(choke_module_init)
|
|
module_exit(choke_module_exit)
|
|
|
|
MODULE_LICENSE("GPL");
|