[PATCH v2 net 0/2] ieee802154: 6lowpan: fix transmit address handling

[Eric Dumazet <edumazet@kernel.org>]

SEFCOM lab reported a warning in lowpan_compress_addr_64(),
triggered by an AF_PACKET socket sending on a lowpan device.

lowpan_header_create() stores the 802.15.4 addresses in the skb
headroom, where lowpan_xmit() cannot tell if they are valid.
It also reads the IPv6 header before AF_PACKET SOCK_DGRAM sockets
have copied it.

Patch 1 moves the neighbour short address lookup to lowpan_xmit().

Patch 2 pushes the destination address as an 8 byte pseudo header,
like IPoIB, and lets lowpan_xmit() compute the 802.15.4 addresses.

v2: move skb_reset_network_header() from patch 1 to patch 2.
    In patch 1, hard_header_len is still 40, and the reset left a stale
    transport header for AF_PACKET SOCK_RAW packets (Sashiko).
    The code after patch 2 is unchanged.
v1: https://lore.kernel.org/netdev/20260928183753.3550210-1-edumazet@kernel.org/

Eric Dumazet (2):
  ieee802154: 6lowpan: look up the neighbour short address in
    lowpan_xmit()
  6lowpan: fix warning in lowpan_compress_addr_64()

 net/ieee802154/6lowpan/6lowpan_i.h |   5 ++
 net/ieee802154/6lowpan/core.c      |   4 +-
 net/ieee802154/6lowpan/tx.c        | 128 ++++++++++++++---------------
 3 files changed, 70 insertions(+), 67 deletions(-)

-- 
2.56.0.rc1.315.gc6ed9934b7-goog