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rxrpc: Use the core ICMP/ICMP6 parsers
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Make rxrpc_encap_rcv_err() pass the ICMP/ICMP6 skbuff to ip_icmp_error() or
ipv6_icmp_error() as appropriate to do the parsing rather than trying to do
it in rxrpc.

This pushes an error report onto the UDP socket's error queue and calls
->sk_error_report() from which point rxrpc can pick it up.

It would be preferable to steal the packet directly from ip*_icmp_error()
rather than letting it get queued, but this is probably good enough.

Also note that __udp4_lib_err() calls sk_error_report() twice in some
cases.

Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]
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@dhowells
dhowells committed Nov 8, 2022
1 parent 42fb06b commit b6c66c4
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Showing 3 changed files with 42 additions and 217 deletions.
1 change: 0 additions & 1 deletion net/rxrpc/ar-internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -998,7 +998,6 @@ void rxrpc_send_keepalive(struct rxrpc_peer *);
/*
* peer_event.c
*/
void rxrpc_encap_err_rcv(struct sock *, struct sk_buff *, int, __be16, u32, u8 *);
void rxrpc_error_report(struct sock *);
void rxrpc_peer_keepalive_worker(struct work_struct *);

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13 changes: 13 additions & 0 deletions net/rxrpc/local_object.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,19 @@
static void rxrpc_local_processor(struct work_struct *);
static void rxrpc_local_rcu(struct rcu_head *);

/*
* Handle an ICMP/ICMP6 error turning up at the tunnel. Push it through the
* usual mechanism so that it gets parsed and presented through the UDP
* socket's error_report().
*/
static void rxrpc_encap_err_rcv(struct sock *sk, struct sk_buff *skb, int err,
__be16 port, u32 info, u8 *payload)
{
if (ip_hdr(skb)->version == IPVERSION)
return ip_icmp_error(sk, skb, err, port, info, payload);
return ipv6_icmp_error(sk, skb, err, port, info, payload);
}

/*
* Compare a local to an address. Return -ve, 0 or +ve to indicate less than,
* same or greater than.
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245 changes: 29 additions & 216 deletions net/rxrpc/peer_event.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,220 +16,12 @@
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include <net/icmp.h>
#include "ar-internal.h"

static void rxrpc_adjust_mtu(struct rxrpc_peer *, unsigned int);
static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *);
static void rxrpc_distribute_error(struct rxrpc_peer *, int,
enum rxrpc_call_completion);

/*
* Find the peer associated with an ICMPv4 packet.
*/
static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
struct sk_buff *skb,
__be16 udp_port,
struct sockaddr_rxrpc *srx)
{
struct iphdr *ip, *ip0 = ip_hdr(skb);
struct icmphdr *icmp = icmp_hdr(skb);

_enter("%u,%u,%u", ip0->protocol, icmp->type, icmp->code);

switch (icmp->type) {
case ICMP_DEST_UNREACH:
case ICMP_TIME_EXCEEDED:
case ICMP_PARAMETERPROB:
ip = (struct iphdr *)((void *)icmp + 8);
break;
default:
return NULL;
}

memset(srx, 0, sizeof(*srx));
srx->transport_type = local->srx.transport_type;
srx->transport_len = local->srx.transport_len;
srx->transport.family = local->srx.transport.family;

/* Can we see an ICMP4 packet on an ICMP6 listening socket? and vice
* versa?
*/
switch (srx->transport.family) {
case AF_INET:
srx->transport_len = sizeof(srx->transport.sin);
srx->transport.family = AF_INET;
srx->transport.sin.sin_port = udp_port;
memcpy(&srx->transport.sin.sin_addr, &ip->daddr,
sizeof(struct in_addr));
break;

#ifdef CONFIG_AF_RXRPC_IPV6
case AF_INET6:
srx->transport_len = sizeof(srx->transport.sin);
srx->transport.family = AF_INET;
srx->transport.sin.sin_port = udp_port;
memcpy(&srx->transport.sin.sin_addr, &ip->daddr,
sizeof(struct in_addr));
break;
#endif

default:
WARN_ON_ONCE(1);
return NULL;
}

_net("ICMP {%pISp}", &srx->transport);
return rxrpc_lookup_peer_rcu(local, srx);
}

#ifdef CONFIG_AF_RXRPC_IPV6
/*
* Find the peer associated with an ICMPv6 packet.
*/
static struct rxrpc_peer *rxrpc_lookup_peer_icmp6_rcu(struct rxrpc_local *local,
struct sk_buff *skb,
__be16 udp_port,
struct sockaddr_rxrpc *srx)
{
struct icmp6hdr *icmp = icmp6_hdr(skb);
struct ipv6hdr *ip, *ip0 = ipv6_hdr(skb);

_enter("%u,%u,%u", ip0->nexthdr, icmp->icmp6_type, icmp->icmp6_code);

switch (icmp->icmp6_type) {
case ICMPV6_DEST_UNREACH:
case ICMPV6_PKT_TOOBIG:
case ICMPV6_TIME_EXCEED:
case ICMPV6_PARAMPROB:
ip = (struct ipv6hdr *)((void *)icmp + 8);
break;
default:
return NULL;
}

memset(srx, 0, sizeof(*srx));
srx->transport_type = local->srx.transport_type;
srx->transport_len = local->srx.transport_len;
srx->transport.family = local->srx.transport.family;

/* Can we see an ICMP4 packet on an ICMP6 listening socket? and vice
* versa?
*/
switch (srx->transport.family) {
case AF_INET:
_net("Rx ICMP6 on v4 sock");
srx->transport_len = sizeof(srx->transport.sin);
srx->transport.family = AF_INET;
srx->transport.sin.sin_port = udp_port;
memcpy(&srx->transport.sin.sin_addr,
&ip->daddr.s6_addr32[3], sizeof(struct in_addr));
break;
case AF_INET6:
_net("Rx ICMP6");
srx->transport.sin.sin_port = udp_port;
memcpy(&srx->transport.sin6.sin6_addr, &ip->daddr,
sizeof(struct in6_addr));
break;
default:
WARN_ON_ONCE(1);
return NULL;
}

_net("ICMP {%pISp}", &srx->transport);
return rxrpc_lookup_peer_rcu(local, srx);
}
#endif /* CONFIG_AF_RXRPC_IPV6 */

/*
* Handle an error received on the local endpoint as a tunnel.
*/
void rxrpc_encap_err_rcv(struct sock *sk, struct sk_buff *skb, int err,
__be16 port, u32 info, u8 *payload)
{
struct sock_extended_err ee;
struct sockaddr_rxrpc srx;
struct rxrpc_local *local;
struct rxrpc_peer *peer;
u8 version = ip_hdr(skb)->version;
u8 type = icmp_hdr(skb)->type;
u8 code = icmp_hdr(skb)->code;

rcu_read_lock();
local = rcu_dereference_sk_user_data(sk);
if (unlikely(!local)) {
rcu_read_unlock();
return;
}

rxrpc_new_skb(skb, rxrpc_skb_received);

switch (ip_hdr(skb)->version) {
case IPVERSION:
peer = rxrpc_lookup_peer_icmp_rcu(local, skb, port, &srx);
break;
#ifdef CONFIG_AF_RXRPC_IPV6
case 6:
peer = rxrpc_lookup_peer_icmp6_rcu(local, skb, port, &srx);
break;
#endif
default:
rcu_read_unlock();
return;
}

if (peer && !rxrpc_get_peer_maybe(peer))
peer = NULL;
if (!peer) {
rcu_read_unlock();
return;
}

memset(&ee, 0, sizeof(ee));

switch (version) {
case IPVERSION:
if (type == ICMP_DEST_UNREACH &&
code == ICMP_FRAG_NEEDED) {
rxrpc_adjust_mtu(peer, info);
rcu_read_unlock();
rxrpc_put_peer(peer);
return;
}

ee.ee_origin = SO_EE_ORIGIN_ICMP;
ee.ee_type = type;
ee.ee_code = code;
ee.ee_errno = err;
break;

#ifdef CONFIG_AF_RXRPC_IPV6
case 6:
if (type == ICMPV6_PKT_TOOBIG) {
rxrpc_adjust_mtu(peer, info);
rcu_read_unlock();
rxrpc_put_peer(peer);
return;
}

if (err == EACCES)
err = EHOSTUNREACH;

ee.ee_origin = SO_EE_ORIGIN_ICMP6;
ee.ee_type = type;
ee.ee_code = code;
ee.ee_errno = err;
break;
#endif
}

trace_rxrpc_rx_icmp(peer, &ee, &srx);

rxrpc_distribute_error(peer, err, RXRPC_CALL_NETWORK_ERROR);
rcu_read_unlock();
rxrpc_put_peer(peer);
}

/*
* Find the peer associated with a local error.
*/
Expand All @@ -246,6 +38,9 @@ static struct rxrpc_peer *rxrpc_lookup_peer_local_rcu(struct rxrpc_local *local,
srx->transport_len = local->srx.transport_len;
srx->transport.family = local->srx.transport.family;

/* Can we see an ICMP4 packet on an ICMP6 listening socket? and vice
* versa?
*/
switch (srx->transport.family) {
case AF_INET:
srx->transport_len = sizeof(srx->transport.sin);
Expand Down Expand Up @@ -375,20 +170,38 @@ void rxrpc_error_report(struct sock *sk)
}
rxrpc_new_skb(skb, rxrpc_skb_received);
serr = SKB_EXT_ERR(skb);
if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
_leave("UDP empty message");
rcu_read_unlock();
rxrpc_free_skb(skb, rxrpc_skb_freed);
return;
}

if (serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL) {
peer = rxrpc_lookup_peer_local_rcu(local, skb, &srx);
if (peer && !rxrpc_get_peer_maybe(peer))
peer = NULL;
if (peer) {
trace_rxrpc_rx_icmp(peer, &serr->ee, &srx);
rxrpc_store_error(peer, serr);
}
peer = rxrpc_lookup_peer_local_rcu(local, skb, &srx);
if (peer && !rxrpc_get_peer_maybe(peer))
peer = NULL;
if (!peer) {
rcu_read_unlock();
rxrpc_free_skb(skb, rxrpc_skb_freed);
_leave(" [no peer]");
return;
}

trace_rxrpc_rx_icmp(peer, &serr->ee, &srx);

if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
serr->ee.ee_type == ICMP_DEST_UNREACH &&
serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
rxrpc_adjust_mtu(peer, serr->ee.ee_info);
goto out;
}

rxrpc_store_error(peer, serr);
out:
rcu_read_unlock();
rxrpc_free_skb(skb, rxrpc_skb_freed);
rxrpc_put_peer(peer);

_leave("");
}

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