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 <david(a)gibson.dropbear.id.au>
Signed-off-by: Jon Maloy <jmaloy(a)redhat.com>
---
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
v4: -Changed test on (mode == PASST) to (mode != PASTA) as
suggested by Stefano Brivio.
v5: -Updated text in man pages as suggested by Stefano Brivio.
---
conf.c | 7 ++++++-
fwd.c | 2 +-
passt.1 | 5 +++++
passt.h | 2 ++
4 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/conf.c b/conf.c
index eaa7d99..97d8beb 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_PASTA)
+ c->no_splice = 1;
+
if (c->mode == MODE_PASTA && !c->pasta_conf_ns) {
if (copy_routes_opt)
die("--no-copy-routes needs --config-net");
diff --git a/fwd.c b/fwd.c
index 0b7f8b1..2829cd2 100644
--- a/fwd.c
+++ b/fwd.c
@@ -443,7 +443,7 @@ uint8_t fwd_nat_from_host(const struct ctx *c, uint8_t proto,
else if (proto == IPPROTO_UDP)
tgt->eport += c->udp.fwd_in.delta[tgt->eport];
- if (c->mode == MODE_PASTA && inany_is_loopback(&ini->eaddr)
&&
+ if (!c->no_splice && inany_is_loopback(&ini->eaddr) &&
(proto == IPPROTO_TCP || proto == IPPROTO_UDP)) {
/* spliceable */
diff --git a/passt.1 b/passt.1
index b2896a2..d9cd33e 100644
--- a/passt.1
+++ b/passt.1
@@ -695,6 +695,11 @@ Configure MAC address \fIaddr\fR on the tap interface in the
namespace.
Default is to let the tap driver build a pseudorandom hardware address.
+.TP
+.BR \-\-no-splice
+Disable the bypass path for inbound, local traffic. See the section \fBHandling
+of local traffic in pasta\fR in the \fBNOTES\fR for more details.
+
.SH EXAMPLES
.SS \fBpasta
diff --git a/passt.h b/passt.h
index c038630..0dd4efa 100644
--- a/passt.h
+++ b/passt.h
@@ -229,6 +229,7 @@ struct ip6_ctx {
* @no_dhcpv6: Disable DHCPv6 server
* @no_ndp: Disable NDP handler altogether
* @no_ra: Disable router advertisements
+ * @no_splice: Disable socket splicing for inbound traffic
* @host_lo_to_ns_lo: Map host loopback addresses to ns loopback addresses
* @freebind: Allow binding of non-local addresses for forwarding
* @low_wmem: Low probed net.core.wmem_max
@@ -291,6 +292,7 @@ struct ctx {
int no_dhcpv6;
int no_ndp;
int no_ra;
+ int no_splice;
int host_lo_to_ns_lo;
int freebind;
--
2.47.1