Bug 204593
| Summary: | listen(2): outdated "backlog" argument description | ||
|---|---|---|---|
| Product: | Documentation | Reporter: | Michael Orlitzky (michael) |
| Component: | man-pages | Assignee: | documentation_man-pages (documentation_man-pages) |
| Status: | NEW --- | ||
| Severity: | normal | ||
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | Subsystem: | ||
| Regression: | No | Bisected commit-id: | |
The documentation for the "backlog" argument to the listen() call says... The behavior of the backlog argument on TCP sockets changed with Linux 2.2. Now it specifies the queue length for completely established sockets waiting to be accepted, instead of the number of incomplete connection requests. The maximum length of the queue for incomplete sockets can be set using /proc/sys/net/ipv4/tcp_max_syn_backlog. When syncookies are enabled there is no logical maximum length and this set‐ ting is ignored. See tcp(7) for more information. However, I believe this changed with linux-4.3 in commit ef547f2ac16bd9d: https://github.com/torvalds/linux/commit/ef547f2ac16bd9d77a780a0e7c70857e69e8f23f#diff-56ecfd3cd70d57cde321f395f0d8d743L43 Now, the test for the SYN queue is against sk_listener->sk_max_ack_backlog, which include/net/sock.h tells me is * @sk_max_ack_backlog: listen backlog set in listen() In other words, I think the "backlog" argument for listen() now applies to incomplete connections as well.