git: if_tun: Fix error handling, input validation and minor issues

[Aaron LI]

commit 1405477991eed41c116c6126a14150283c0dbae8
Author: Aaron LI <aly at aaronly.me>
Date:   Sun Oct 11 13:14:01 2026 +0800

    if_tun: Fix error handling, input validation and minor issues
    
    * tunclone(): Handle unit allocation failure; rollback changes if
      if_clone_create() fails.
    * tuncreate(): Handle if_alloc() failure to not leak the 'sc'.
    * tun_clone_create(): Simplify bitmap unit conflict, which is an
      out-of-sync and shouldn't happen; rollback changes if tuncreate()
      fails.
    * tunifioctl(): Use ksnprintf() to avoid possible ifs->ascii overrun.
    * tunifoutput_serialized():
      - Drop packets if the interface is not up, like FreeBSD.
      - Handle short or fragmented packets from BPF writes.
      - Fix ifq_classify() by moving it after the BPF handling.
      - Add IFNET_STAT_INC() for obytes.
    * tunioctl():
      - Validate MTU range, similar to the check done in if.c.
      - Clear the IFF_MULTICAST bit.
    * tunwrite(): Simplify and optimize mbuf chain building by using
      m_uiomove(), which uses mbuf clusters to save allocations.
    * Refresh the man page.
    
    Some fixes/updates are derived from the FreeBSD code.
    
    Assisted-by: Claude Sonnet 5

Summary of changes:
 share/man/man4/tun.4 | 184 +++++++++++++++++++++++++++------------------------
 sys/net/tun/if_tun.c | 153 +++++++++++++++++++++++++-----------------
 2 files changed, 190 insertions(+), 147 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/1405477991eed41c116c6126a14150283c0dbae8


-- 
DragonFly BSD source repository