aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorMichael Brown <mcb30@ipxe.org>2015-06-29 14:50:16 +0100
committerMichael Brown <mcb30@ipxe.org>2015-06-29 14:50:16 +0100
commit8829634bd7188bdfa5528421a8bbecf39c498f40 (patch)
tree1b5f2aa8169c91c97b286632f3119228ea1eb32e
parente213a008ca448c41f617d4565e0473ca705e69b3 (diff)
downloadipxe-8829634bd7188bdfa5528421a8bbecf39c498f40.zip
ipxe-8829634bd7188bdfa5528421a8bbecf39c498f40.tar.gz
ipxe-8829634bd7188bdfa5528421a8bbecf39c498f40.tar.bz2
[ipoib] Attempt to generate ARPs as needed to repopulate REMAC cache
The only way to map an eIPoIB MAC address (REMAC) to an IPoIB MAC address is to intercept an incoming ARP request or reply. If we do not have an REMAC cache entry for a particular destination MAC address, then we cannot transmit the packet. This can arise in at least two situations: - An external program (e.g. a PXE NBP using the UNDI API) may attempt to transmit to a destination MAC address that has been obtained by some method other than ARP. - Memory pressure may have caused REMAC cache entries to be discarded. This is fairly likely on a busy network, since REMAC cache entries are created for all received (broadcast) ARP requests. (We can't sensibly avoid creating these cache entries, since they are required in order to send an ARP reply, and when we are being used via the UNDI API we may have no knowledge of which IP addresses are "ours".) Attempt to ameliorate the situation by generating a semi-spurious ARP request whenever we find a missing REMAC cache entry. This will hopefully trigger an ARP reply, which would then provide us with the information required to populate the REMAC cache. Signed-off-by: Michael Brown <mcb30@ipxe.org>
-rw-r--r--src/drivers/net/ipoib.c55
-rw-r--r--src/include/ipxe/arp.h4
-rw-r--r--src/net/arp.c6
3 files changed, 57 insertions, 8 deletions
diff --git a/src/drivers/net/ipoib.c b/src/drivers/net/ipoib.c
index b72e8fc..bec4bba 100644
--- a/src/drivers/net/ipoib.c
+++ b/src/drivers/net/ipoib.c
@@ -33,8 +33,10 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <ipxe/errortab.h>
#include <ipxe/malloc.h>
#include <ipxe/if_arp.h>
+#include <ipxe/arp.h>
#include <ipxe/if_ether.h>
#include <ipxe/ethernet.h>
+#include <ipxe/ip.h>
#include <ipxe/iobuf.h>
#include <ipxe/netdevice.h>
#include <ipxe/infiniband.h>
@@ -48,6 +50,20 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
* IP over Infiniband
*/
+/* Disambiguate the various error causes */
+#define ENXIO_ARP_REPLY __einfo_error ( EINFO_ENXIO_ARP_REPLY )
+#define EINFO_ENXIO_ARP_REPLY \
+ __einfo_uniqify ( EINFO_ENXIO, 0x01, \
+ "Missing REMAC for ARP reply target address" )
+#define ENXIO_NON_IPV4 __einfo_error ( EINFO_ENXIO_NON_IPV4 )
+#define EINFO_ENXIO_NON_IPV4 \
+ __einfo_uniqify ( EINFO_ENXIO, 0x02, \
+ "Missing REMAC for non-IPv4 packet" )
+#define ENXIO_ARP_SENT __einfo_error ( EINFO_ENXIO_ARP_SENT )
+#define EINFO_ENXIO_ARP_SENT \
+ __einfo_uniqify ( EINFO_ENXIO, 0x03, \
+ "Missing REMAC for IPv4 packet (ARP sent)" )
+
/** Number of IPoIB send work queue entries */
#define IPOIB_NUM_SEND_WQES 2
@@ -336,8 +352,11 @@ static int ipoib_translate_tx_arp ( struct net_device *netdev,
/* Look up REMAC, if applicable */
if ( arphdr->ar_op == ARPOP_REPLY ) {
target_ha = ipoib_find_remac ( ipoib, arp_target_pa ( arphdr ));
- if ( ! target_ha )
- return -ENXIO;
+ if ( ! target_ha ) {
+ DBGC ( ipoib, "IPoIB %p no REMAC for %s ARP reply\n",
+ ipoib, eth_ntoa ( arp_target_pa ( arphdr ) ) );
+ return -ENXIO_ARP_REPLY;
+ }
}
/* Construct new packet */
@@ -473,6 +492,7 @@ static int ipoib_transmit ( struct net_device *netdev,
struct ipoib_device *ipoib = netdev->priv;
struct ib_device *ibdev = ipoib->ibdev;
struct ethhdr *ethhdr;
+ struct iphdr *iphdr;
struct ipoib_hdr *ipoib_hdr;
struct ipoib_mac *mac;
struct ib_address_vector dest;
@@ -497,9 +517,34 @@ static int ipoib_transmit ( struct net_device *netdev,
iob_pull ( iobuf, sizeof ( *ethhdr ) );
/* Identify destination address */
- mac = ipoib_find_remac ( ipoib, ( ( void *) ethhdr->h_dest ) );
- if ( ! mac )
- return -ENXIO;
+ mac = ipoib_find_remac ( ipoib, ( ( void * ) ethhdr->h_dest ) );
+ if ( ! mac ) {
+ /* Generate a new ARP request (if possible) to trigger
+ * population of the REMAC cache entry.
+ */
+ if ( ( net_proto != htons ( ETH_P_IP ) ) ||
+ ( iob_len ( iobuf ) < sizeof ( *iphdr ) ) ) {
+ DBGC ( ipoib, "IPoIB %p no REMAC for %s non-IPv4 "
+ "packet type %04x\n", ipoib,
+ eth_ntoa ( ethhdr->h_dest ),
+ ntohs ( net_proto ) );
+ return -ENXIO_NON_IPV4;
+ }
+ iphdr = iobuf->data;
+ if ( ( rc = arp_tx_request ( netdev, &ipv4_protocol,
+ &iphdr->dest, &iphdr->src ) ) !=0){
+ DBGC ( ipoib, "IPoIB %p could not ARP for %s/%s/",
+ ipoib, eth_ntoa ( ethhdr->h_dest ),
+ inet_ntoa ( iphdr->dest ) );
+ DBGC ( ipoib, "%s: %s\n", inet_ntoa ( iphdr->src ),
+ strerror ( rc ) );
+ return rc;
+ }
+ DBGC ( ipoib, "IPoIB %p no REMAC for %s/%s/", ipoib,
+ eth_ntoa ( ethhdr->h_dest ), inet_ntoa ( iphdr->dest ) );
+ DBGC ( ipoib, "%s\n", inet_ntoa ( iphdr->src ) );
+ return -ENXIO_ARP_SENT;
+ }
/* Translate packet if applicable */
if ( ( rc = ipoib_translate_tx ( netdev, iobuf, net_proto ) ) != 0 )
diff --git a/src/include/ipxe/arp.h b/src/include/ipxe/arp.h
index 9319501..5822fa0 100644
--- a/src/include/ipxe/arp.h
+++ b/src/include/ipxe/arp.h
@@ -57,4 +57,8 @@ static inline int arp_tx ( struct io_buffer *iobuf, struct net_device *netdev,
&arp_discovery, net_source, ll_source );
}
+extern int arp_tx_request ( struct net_device *netdev,
+ struct net_protocol *net_protocol,
+ const void *net_dest, const void *net_source );
+
#endif /* _IPXE_ARP_H */
diff --git a/src/net/arp.c b/src/net/arp.c
index 663dc00..1e27c44 100644
--- a/src/net/arp.c
+++ b/src/net/arp.c
@@ -56,9 +56,9 @@ struct net_protocol arp_protocol __net_protocol;
* @v net_source Source network-layer address
* @ret rc Return status code
*/
-static int arp_tx_request ( struct net_device *netdev,
- struct net_protocol *net_protocol,
- const void *net_dest, const void *net_source ) {
+int arp_tx_request ( struct net_device *netdev,
+ struct net_protocol *net_protocol,
+ const void *net_dest, const void *net_source ) {
struct ll_protocol *ll_protocol = netdev->ll_protocol;
struct io_buffer *iobuf;
struct arphdr *arphdr;