Re: [PATCH v3] pasta: make it possible to disable socket splicing

On Thu, Dec 05, 2024 at 09:06:26PM +0100, Stefano Brivio wrote:

On Tue, 3 Dec 2024 16:53:02 -0500 Jon Maloy wrote:

...

During testing it is sometimes useful to force traffic which would normally be forwared by socket splicing through the tap interface.

In this commit, we add a command switch enabling such funtionality for inbound local traffic.

For outbound local traffic this is much trickier, if even possible, so leave that for a later commit.

Suggested-by: David Gibson Signed-off-by: Jon Maloy

--- v2: Some minor changes based on feedback from PASST team v3: More changes based on feedback from D. Gibson and S. Brivio -Moved new option to pasta-only section -Added description to man-page --- conf.c | 7 ++++++- fwd.c | 2 +- passt.1 | 4 ++++ passt.h | 2 ++ 4 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/conf.c b/conf.c index eaa7d99..53f6770 100644 --- a/conf.c +++ b/conf.c @@ -977,7 +977,8 @@ pasta_opts: " Don't copy all routes to namespace\n" " --no-copy-addrs DEPRECATED:\n" " Don't copy all addresses to namespace\n" - " --ns-mac-addr ADDR Set MAC address on tap interface\n"); + " --ns-mac-addr ADDR Set MAC address on tap interface\n" + " --no-splice Disable inbound socket splicing\n");

exit(status); } @@ -1319,6 +1320,7 @@ void conf(struct ctx *c, int argc, char **argv) {"no-dhcpv6", no_argument, &c->no_dhcpv6, 1 }, {"no-ndp", no_argument, &c->no_ndp, 1 }, {"no-ra", no_argument, &c->no_ra, 1 }, + {"no-splice", no_argument, &c->no_splice, 1 }, {"freebind", no_argument, &c->freebind, 1 }, {"no-map-gw", no_argument, &no_map_gw, 1 }, {"ipv4-only", no_argument, NULL, '4' }, @@ -1756,6 +1758,9 @@ void conf(struct ctx *c, int argc, char **argv) } } while (name != -1);

+ if (c->mode == MODE_PASST) + c->no_splice = 1;

Oops, sorry, I missed this during review, but tests caught it: this needs to be if (c->mode != MODE_PASTA) to also include the MODE_VU case, otherwise:

Good point. Sorry I missed this on review. -- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson