#include <linux/random.h>
#include <linux/slab.h>
#include <linux/string.h>
+#include <linux/vmalloc.h>
#include <net/request_sock.h>
+/*
+ * Maximum number of SYN_RECV sockets in queue per LISTEN socket.
+ * One SYN_RECV socket costs about 80bytes on a 32bit machine.
+ * It would be better to replace it with a global counter for all sockets
+ * but then some measure against one socket starving all other sockets
+ * would be needed.
+ *
+ * It was 128 by default. Experiments with real servers show, that
+ * it is absolutely not enough even at 100conn/sec. 256 cures most
+ * of problems. This value is adjusted to 128 for very small machines
+ * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb).
+ * Note : Dont forget somaxconn that may limit backlog too.
+ */
+int sysctl_max_syn_backlog = 256;
+
int reqsk_queue_alloc(struct request_sock_queue *queue,
- const int nr_table_entries)
+ unsigned int nr_table_entries)
{
- const int lopt_size = sizeof(struct listen_sock) +
- nr_table_entries * sizeof(struct request_sock *);
- struct listen_sock *lopt = kmalloc(lopt_size, GFP_KERNEL);
+ size_t lopt_size = sizeof(struct listen_sock);
+ struct listen_sock *lopt;
+ nr_table_entries = min_t(u32, nr_table_entries, sysctl_max_syn_backlog);
+ nr_table_entries = max_t(u32, nr_table_entries, 8);
+ nr_table_entries = roundup_pow_of_two(nr_table_entries + 1);
+ lopt_size += nr_table_entries * sizeof(struct request_sock *);
+ if (lopt_size > PAGE_SIZE)
+ lopt = __vmalloc(lopt_size,
+ GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
+ PAGE_KERNEL);
+ else
+ lopt = kzalloc(lopt_size, GFP_KERNEL);
if (lopt == NULL)
return -ENOMEM;
- memset(lopt, 0, lopt_size);
-
- for (lopt->max_qlen_log = 6;
- (1 << lopt->max_qlen_log) < sysctl_max_syn_backlog;
+ for (lopt->max_qlen_log = 3;
+ (1 << lopt->max_qlen_log) < nr_table_entries;
lopt->max_qlen_log++);
get_random_bytes(&lopt->hash_rnd, sizeof(lopt->hash_rnd));
rwlock_init(&queue->syn_wait_lock);
- queue->rskq_accept_head = queue->rskq_accept_head = NULL;
+ queue->rskq_accept_head = NULL;
+ lopt->nr_table_entries = nr_table_entries;
write_lock_bh(&queue->syn_wait_lock);
queue->listen_opt = lopt;
}
EXPORT_SYMBOL(reqsk_queue_alloc);
+
+void reqsk_queue_destroy(struct request_sock_queue *queue)
+{
+ /* make all the listen_opt local to us */
+ struct listen_sock *lopt = reqsk_queue_yank_listen_sk(queue);
+ size_t lopt_size = sizeof(struct listen_sock) +
+ lopt->nr_table_entries * sizeof(struct request_sock *);
+
+ if (lopt->qlen != 0) {
+ unsigned int i;
+
+ for (i = 0; i < lopt->nr_table_entries; i++) {
+ struct request_sock *req;
+
+ while ((req = lopt->syn_table[i]) != NULL) {
+ lopt->syn_table[i] = req->dl_next;
+ lopt->qlen--;
+ reqsk_free(req);
+ }
+ }
+ }
+
+ BUG_TRAP(lopt->qlen == 0);
+ if (lopt_size > PAGE_SIZE)
+ vfree(lopt);
+ else
+ kfree(lopt);
+}
+
+EXPORT_SYMBOL(reqsk_queue_destroy);