A RST segment can be sent in response to (a) received segment or (b) by the upper layer protocol. The SEG.SEQ validation consists of two checks: (1) the in-window check of SEG.SEQ and (2) the exact match check of SEG.SEQ. For the in-window check (1), the left edge of the window needs to be based on tp->last_ack_sent to cover the delayed ACK case, whereas the right edge needs to be based on tp->rcv_nxt + tp->rcv_wnd. This both assumes that tp->rcv_wnd is not zero. For the special case of tp->rcv_wnd being zero, add checks against tp->last_ack_sent for (a) and on tp->rcv_nxt for (b). This applies to all TCP stacks. When the exact match (2) of SEG.SEQ is performed, it should be based on tp->last_ack_sent for (a) and on tp->rcv_nxt for (b). To cover both, check for both. Add this only to the base stack, since the RACK and BBR stacks already do this. PR: 296594 Reviewed by: rscheff MFC after: 3 days MFC to: stable/14 MFC to: stable/15 Sponsored by: Netflix, Inc. Differential Revision: https://reviews.freebsd.org/D58594
FreeBSD Source:
This is the top level of the FreeBSD source directory.
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For copyright information, please see the file COPYRIGHT in this directory. Additional copyright information also exists for some sources in this tree - please see the specific source directories for more information.
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Source Roadmap:
| Directory | Description |
|---|---|
| bin | System/user commands. |
| cddl | Source code for third-party software under the Common Development and Distribution License. |
| contrib | Source code for third-party software. |
| crypto | Source code for cryptographic libraries and commands (see crypto/README). |
| etc | Template files for /etc. |
| include | System include files. |
| kerberos5 | Build system for Kerberos 5 (Heimdal). |
| krb5 | Build system for Kerberos 5 (MIT). |
| lib | System libraries. |
| libexec | System commands intended to be executed by other commands or daemons. |
| packages | Base system packages. |
| release | Makefiles and scripts used for building releases and VM images. |
| rescue | Build system for statically linked /rescue commands. |
| sbin | System commands. |
| secure | Build system for cryptographic libraries and commands (excluding Kerberos). |
| share | Shared resources. |
| stand | Boot loader sources. |
| sys | Kernel sources (see sys/README.md). |
| targets | Support for experimental DIRDEPS_BUILD |
| tests | Tests which can be run by Kyua. See tests/README for additional information. |
| tools | Ancillary utilities and tests (not included in the build). |
| usr.bin | User commands. |
| usr.sbin | System administration commands. |
For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see FreeBSD Handbook.