From: Christian Hopps <redacted>

Add a new xfrm mode implementing AggFrag/IP-TFS from RFC9347.

This utilizes the new xfrm_mode_cbs to implement demand-driven IP-TFS
functionality. This functionality can be used to increase bandwidth
utilization through small packet aggregation, as well as help solve PMTU
issues through it's efficient use of fragmentation.

   Link: https://www.rfc-editor.org/rfc/rfc9347.txt

Multiple commits follow to build the functionality into xfrm_iptfs.c

Signed-off-by: Christian Hopps <redacted>
---
  net/xfrm/Makefile     |   1 +
  net/xfrm/xfrm_iptfs.c | 225 ++++++++++++++++++++++++++++++++++++++++++
  2 files changed, 226 insertions(+)
  create mode 100644 net/xfrm/xfrm_iptfs.c

diff --git a/net/xfrm/Makefile b/net/xfrm/Makefile
index 547cec77ba03..cd6520d4d777 100644
--- a/net/xfrm/Makefile
+++ b/net/xfrm/Makefile

@@ -20,5 +20,6 @@ obj-$(CONFIG_XFRM_USER) += xfrm_user.o
  obj-$(CONFIG_XFRM_USER_COMPAT) += xfrm_compat.o
  obj-$(CONFIG_XFRM_IPCOMP) += xfrm_ipcomp.o
  obj-$(CONFIG_XFRM_INTERFACE) += xfrm_interface.o
+obj-$(CONFIG_XFRM_IPTFS) += xfrm_iptfs.o
  obj-$(CONFIG_XFRM_ESPINTCP) += espintcp.o
  obj-$(CONFIG_DEBUG_INFO_BTF) += xfrm_state_bpf.o

diff --git a/net/xfrm/xfrm_iptfs.c b/net/xfrm/xfrm_iptfs.c
new file mode 100644
index 000000000000..e7b5546e1f6a
--- /dev/null
+++ b/net/xfrm/xfrm_iptfs.c

@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0