vpp: T9484: keep net.core.rmem_max at VPP's netlink buffer size

VPP requests a 256 MiB netlink receive buffer (nl-rx-buffer-size), but
the kernel caps it at net.core.rmem_max, which VyOS sets to 2 MiB, so
VPP gets 4 MiB. A large routing table over VPP interfaces can overflow
it, and linux-cp then falls back to a full resync.

Setting the sysctl from the CLI does not help at boot: system sysctl
runs after vpp, so VPP has already opened its socket.

- vpp.py raises net.core.rmem_max to the requested size before VPP is
  (re)started; a higher value is kept.
- VPP re-opens its netlink socket on every resync and sizes it again, so
  system sysctl no longer applies a lower value while VPP is configured;
  it uses the required size and prints a warning.
- When VPP is removed, vpp.py sets net.core.rmem_max back to the value
  from system sysctl, or to the default from sysctl.d, read with the new
  vyos.utils.system.sysctl_read_default().
- startup.conf.j2 takes nl-rx-buffer-size from the same value
  (default_resource_map) instead of its own constant.

0 files changed, 0 insertions, 0 deletions