[Swan-dev] [PATCH libreswan v2 3/3] kernel, netlink: Add support for nic_offload='auto' mode

ilant at mellanox.com ilant at mellanox.com
Wed Aug 2 15:22:28 UTC 2017


From: Ilan Tayari <ilant at mellanox.com>

Detect kernel capability when adding the first interface.
Ethtool IOCTL requires a valid device, so this cannot be done
before that.

Detect per-device capability using ethtool features when
enumerating devices.

Signed-off-by: Ilan Tayari <ilant at mellanox.com>
---
 programs/pluto/kernel.c         |  31 ++++++++++--
 programs/pluto/kernel.h         |   3 +-
 programs/pluto/kernel_netlink.c | 101 +++++++++++++++++++++++++++++++++++++++-
 programs/pluto/server.h         |   7 +++
 4 files changed, 134 insertions(+), 8 deletions(-)

diff --git a/programs/pluto/kernel.c b/programs/pluto/kernel.c
index 9b14caf21..1297db7d9 100644
--- a/programs/pluto/kernel.c
+++ b/programs/pluto/kernel.c
@@ -1714,6 +1714,23 @@ static bool del_spi(ipsec_spi_t spi, int proto,
 	return kernel_ops->del_sa(&sa);
 }
 
+static void setup_esp_nic_offload(struct kernel_sa *sa, struct connection *c,
+		bool *nic_offload_fallback)
+{
+	if (c->nic_offload == nic_offload_no)
+		return;
+	if (!c->interface || !c->interface->ip_dev ||
+		!c->interface->ip_dev->id_rname)
+		return;
+
+	if (c->nic_offload == nic_offload_auto) {
+		if (c->interface->ip_dev->id_nic_offload != IFNO_SUPPORTED)
+			return;
+		*nic_offload_fallback = TRUE;
+	}
+	sa->nic_offload_dev = c->interface->ip_dev->id_rname;
+}
+
 /*
  * Set up one direction of the SA bundle
  */
@@ -1732,6 +1749,8 @@ static bool setup_half_ipsec_sa(struct state *st, bool inbound)
 	bool incoming_ref_set = FALSE;
 	IPsecSAref_t refhim = st->st_refhim;
 	IPsecSAref_t new_refhim = IPSEC_SAREF_NULL;
+	bool nic_offload_fallback = FALSE;
+	bool ret;
 
 	/* SPIs, saved for spigrouping or undoing, if necessary */
 	struct kernel_sa said[EM_MAXRELSPIS];
@@ -1794,9 +1813,6 @@ static bool setup_half_ipsec_sa(struct state *st, bool inbound)
 	said_boilerplate.transport_proto = c->spd.this.protocol;
 	said_boilerplate.sa_lifetime = c->sa_ipsec_life_seconds;
 	said_boilerplate.outif = -1;
-	said_boilerplate.nic_offload = c->nic_offload;
-	if (c->nic_offload && c->interface != NULL)
-		said_boilerplate.nic_offload_ifindex = if_nametoindex(c->interface->ip_dev->id_rname);
 
 #ifdef HAVE_LABELED_IPSEC
 	said_boilerplate.sec_ctx = st->sec_ctx;
@@ -2286,8 +2302,15 @@ static bool setup_half_ipsec_sa(struct state *st, bool inbound)
 			said_next->ref = refhim;
 			outgoing_ref_set = TRUE;
 		}
+		setup_esp_nic_offload(said_next, c, &nic_offload_fallback);
 
-		if (!kernel_ops->add_sa(said_next, replace)) {
+		ret = kernel_ops->add_sa(said_next, replace);
+		if (!ret && said_next->nic_offload_dev && nic_offload_fallback) {
+			/* Fallback to non-nic-offload crypto */
+			said_next->nic_offload_dev = NULL;
+			ret = kernel_ops->add_sa(said_next, replace);
+		}
+		if (!ret) {
 			/* scrub keys from memory */
 			memset(said_next->enckey, 0, said_next->enckeylen);
 			memset(said_next->authkey, 0, said_next->authkeylen);
diff --git a/programs/pluto/kernel.h b/programs/pluto/kernel.h
index 0b6b20c8c..bf519fe70 100644
--- a/programs/pluto/kernel.h
+++ b/programs/pluto/kernel.h
@@ -117,8 +117,7 @@ struct kernel_sa {
 #ifdef HAVE_LABELED_IPSEC
 	struct xfrm_user_sec_ctx_ike *sec_ctx;
 #endif
-	bool nic_offload;
-	int nic_offload_ifindex;
+	const char *nic_offload_dev;
 
 	deltatime_t sa_lifetime; /* number of seconds until SA expires */
 	/* below two need to enabled and used, instead of getting passed */
diff --git a/programs/pluto/kernel_netlink.c b/programs/pluto/kernel_netlink.c
index 13ad2e6f3..1c5816721 100644
--- a/programs/pluto/kernel_netlink.c
+++ b/programs/pluto/kernel_netlink.c
@@ -38,8 +38,11 @@
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/types.h>
+#include <sys/ioctl.h>
 #include <stdint.h>
 #include <linux/pfkeyv2.h>
+#include <linux/ethtool.h>
+#include <linux/sockios.h>
 #include <unistd.h>
 
 #include "kameipsec.h"
@@ -81,6 +84,9 @@
 /* Minimum priority number in SPD used by pluto. */
 #define MIN_SPD_PRIORITY 1024
 
+#define NIC_OFFLOAD_UNKNOWN -2
+#define NIC_OFFLOAD_UNSUPPORTED -1
+
 struct aead_alg {
 	int id;
 	int icvlen;
@@ -89,6 +95,7 @@ struct aead_alg {
 
 static int netlinkfd = NULL_FD;
 static int netlink_bcast_fd = NULL_FD;
+static int netlink_esp_hw_offload = NIC_OFFLOAD_UNKNOWN;
 
 #define NE(x) { x, #x }	/* Name Entry -- shorthand for sparse_names */
 
@@ -891,6 +898,95 @@ static bool netlink_raw_eroute(const ip_address *this_host,
 	return ok;
 }
 
+static void netlink_find_offload_feature(const char *ifname)
+{
+	struct ethtool_sset_info *sset_info = NULL;
+	struct ethtool_gstrings *cmd = NULL;
+	struct ifreq ifr;
+	uint32_t sset_len, i;
+	char *str;
+	int err;
+
+	netlink_esp_hw_offload = NIC_OFFLOAD_UNSUPPORTED;
+
+	/* Determine number of device-features */
+	sset_info = alloc_bytes(sizeof(*sset_info) + sizeof(sset_info->data[0]), "ethtool_sset_info");
+	sset_info->cmd = ETHTOOL_GSSET_INFO;
+	sset_info->sset_mask = 1ULL << ETH_SS_FEATURES;
+	strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
+	ifr.ifr_data = (void *)sset_info;
+	err = ioctl(netlinkfd, SIOCETHTOOL, &ifr);
+	if (err)
+		goto out;
+
+	if (sset_info->sset_mask != 1ULL << ETH_SS_FEATURES)
+		goto out;
+	sset_len = sset_info->data[0];
+
+	/* Retrieve names of device-features */
+	cmd = alloc_bytes(sizeof(*cmd) + ETH_GSTRING_LEN * sset_len, "ethtool_gstrings");
+	cmd->cmd = ETHTOOL_GSTRINGS;
+	cmd->string_set = ETH_SS_FEATURES;
+	strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
+	ifr.ifr_data = (void *)cmd;
+	err = ioctl(netlinkfd, SIOCETHTOOL, &ifr);
+	if (err)
+		goto out;
+
+	/* Look for the ESP_HW feature bit */
+	str = (char *)cmd->data;
+	for (i = 0; i < cmd->len; i++) {
+		if (strncmp(str, "esp-hw-offload", ETH_GSTRING_LEN) == 0)
+			break;
+		str += ETH_GSTRING_LEN;
+	}
+	if (i >= cmd->len)
+		goto out;
+
+	netlink_esp_hw_offload = i;
+
+out:
+	if (sset_info)
+		pfree(sset_info);
+	if (cmd)
+		pfree(cmd);
+}
+
+static enum iface_nic_offload netlink_detect_offload(const char *ifname)
+{
+	enum iface_nic_offload ret = IFNO_UNSUPPORTED;
+	struct ethtool_gfeatures *cmd;
+	uint32_t feature_bit;
+	struct ifreq ifr;
+	int blocks;
+
+	/*
+	 * Kernel requires a real interface in order to query the kernel-wide
+	 * capability, so we do it here on first invocation
+	 */
+	if (netlink_esp_hw_offload == NIC_OFFLOAD_UNKNOWN)
+		netlink_find_offload_feature(ifname);
+
+	if (netlink_esp_hw_offload == NIC_OFFLOAD_UNSUPPORTED)
+		return ret;
+
+	/* Feature is supported by kernel. Query device features */
+	blocks = (netlink_esp_hw_offload + 31) / 32;
+	feature_bit = 1 << (netlink_esp_hw_offload % 31);
+
+	cmd = alloc_bytes(sizeof(*cmd) + sizeof(cmd->features[0]) * blocks, "ethtool_gfeatures");
+	strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
+	ifr.ifr_data = (void *)cmd;
+	cmd->cmd = ETHTOOL_GFEATURES;
+	cmd->size = blocks;
+	if ((ioctl(netlinkfd, SIOCETHTOOL, &ifr) == 0) &&
+		(cmd->features[blocks-1].active & feature_bit))
+		ret = IFNO_SUPPORTED;
+
+	pfree(cmd);
+	return ret;
+}
+
 /*
  * netlink_add_sa - Add an SA into the kernel SPDB via netlink
  *
@@ -1258,13 +1354,13 @@ static bool netlink_add_sa(const struct kernel_sa *sa, bool replace)
 		attr = (struct rtattr *)((char *)attr + attr->rta_len);
 	}
 
-	if (sa->nic_offload) {
+	if (sa->nic_offload_dev) {
 		struct xfrm_user_offload xuo = { 0, 0 };
 
 		xuo.flags |= sa->inbound ? XFRM_OFFLOAD_INBOUND : 0;
 		if (sa->src->u.v4.sin_family == AF_INET6)
 			xuo.flags |= XFRM_OFFLOAD_IPV6;
-		xuo.ifindex = sa->nic_offload_ifindex;
+		xuo.ifindex = if_nametoindex(sa->nic_offload_dev);
 
 		attr->rta_type = XFRMA_OFFLOAD_DEV;
 		attr->rta_len = RTA_LENGTH(sizeof(xuo));
@@ -2181,6 +2277,7 @@ static void netlink_process_raw_ifaces(struct raw_iface *rifaces)
 				id->id_vname = clone_str(v->name,
 							"virtual device name netlink");
 				id->id_count++;
+				id->id_nic_offload = netlink_detect_offload(ifp->name);
 
 				q->ip_addr = ifp->addr;
 				q->fd = fd;
diff --git a/programs/pluto/server.h b/programs/pluto/server.h
index 31515e8a4..ba18f45aa 100644
--- a/programs/pluto/server.h
+++ b/programs/pluto/server.h
@@ -40,6 +40,12 @@ extern unsigned int pluto_max_halfopen; /* Max allowed half-open IKE SA's before
 extern unsigned int pluto_ddos_threshold; /* Max incoming IKE before activating DCOOKIES */
 extern deltatime_t pluto_shunt_lifetime; /* lifetime before we cleanup bare shunts (for OE) */
 
+/* device_nic_offload: NIC offload capability of an interface */
+enum iface_nic_offload {
+	IFNO_UNSUPPORTED,
+	IFNO_SUPPORTED,
+};
+
 /* interface: a terminal point for IKE traffic, IPsec transport mode
  * and IPsec tunnels.
  * Essentially:
@@ -57,6 +63,7 @@ struct iface_dev {
 	int id_count;
 	char *id_vname; /* virtual (ipsec) device name */
 	char *id_rname; /* real device name */
+	enum iface_nic_offload id_nic_offload;
 };
 
 struct iface_port {
-- 
2.11.0



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