On Tue, 14 May 2024 11:03:37 +1000 David Gibson <david(a)gibson.dropbear.id.au> wrote:Current ICMP hard codes its forwarding rules, and never applies any translations. Change it to use the flow_forward() function, so that it's translated the same as TCP (excluding TCP specific port redirection). This means that gw mapping now applies to ICMP so "ping <gw address>" will now ping the host's loopback instead of the actual gw machine. This removes the surprising behaviour that the target you ping might not be the same as you connect to with TCP. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- flow.c | 1 + icmp.c | 14 ++++++++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/flow.c b/flow.c index a6afe39..b43a079 100644 --- a/flow.c +++ b/flow.c @@ -285,6 +285,7 @@ const struct flowside *flow_initiate_sa(union flow *flow, uint8_t pif, * * Return: pointer to the forwarded flowside information */ +/* cppcheck-suppress unusedFunction */ const struct flowside *flow_forward_af(union flow *flow, uint8_t pif, sa_family_t af, const void *saddr, in_port_t sport, diff --git a/icmp.c b/icmp.c index 0112fd9..6310178 100644 --- a/icmp.c +++ b/icmp.c @@ -153,6 +153,7 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c, sa_family_t af, uint16_t id, const void *saddr, const void *daddr) { + uint8_t proto = af == AF_INET ? IPPROTO_ICMP : IPPROTO_ICMPV6; uint8_t flowtype = af == AF_INET ? FLOW_PING4 : FLOW_PING6; union epoll_ref ref = { .type = EPOLL_TYPE_PING }; union flow *flow = flow_alloc(); @@ -163,9 +164,18 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c, if (!flow) return NULL; - flow_initiate_af(flow, PIF_TAP, af, saddr, id, daddr, id); - flow_forward_af(flow, PIF_HOST, af, NULL, 0, daddr, 0); + if (!flow_forward(c, flow, proto)) + goto cancel; + + if (flow->f.pif[FWDSIDE] != PIF_HOST) { + flow_err(flow, "No support for forwarding %s from %s to %s", + proto == IPPROTO_ICMP ? "ICMP" : "ICMPv6",Which brings me to two remarks: - having the protocol name also in the flow_err() message printed in flow_forward() could be helpful - then, perhaps, we should re-introduce ip_proto_str[] which was dropped with 340164445341 ("epoll: Generalize epoll_ref to cover things other than sockets")+ pif_name(flow->f.pif[INISIDE]), + pif_name(flow->f.pif[FWDSIDE])); + goto cancel; + } + pingf = FLOW_SET_TYPE(flow, flowtype, ping); pingf->seq = -1;-- Stefano