[qca-nss-sfe] Add support for ESP handler in SFE
Provide support for ESP protocol handling in SFE for IPv4 and
IPv6
Change-Id: I7c2adb5e3ab25db48a7fdfd3c61294ddbba382d4
Signed-off-by: Suhas N Bhargav <quic_sbhargav@quicinc.com>
diff --git a/sfe_ipv4_esp.c b/sfe_ipv4_esp.c
new file mode 100644
index 0000000..c21d6a7
--- /dev/null
+++ b/sfe_ipv4_esp.c
@@ -0,0 +1,282 @@
+/*
+ * sfe_ipv4_esp.c
+ * Shortcut forwarding engine - IPv4 ESP implementation
+ *
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <linux/skbuff.h>
+#include <net/protocol.h>
+#include <net/ip.h>
+#include <linux/etherdevice.h>
+#include <linux/lockdep.h>
+
+#include "sfe_debug.h"
+#include "sfe_api.h"
+#include "sfe.h"
+#include "sfe_flow_cookie.h"
+#include "sfe_ipv4.h"
+#include "sfe_ipv4_esp.h"
+
+/*
+ * sfe_ipv4_recv_esp()
+ * Handle ESP packet receives and forwarding
+ */
+int sfe_ipv4_recv_esp(struct sfe_ipv4 *si, struct sk_buff *skb, struct net_device *dev,
+ unsigned int len, struct iphdr *iph, unsigned int ihl,
+ bool sync_on_find, bool tun_outer)
+{
+ struct sfe_ipv4_connection_match *cm;
+ struct net_device *xmit_dev;
+ struct net_protocol *ipprot;
+ netdev_features_t features;
+ bool passthrough;
+ bool bridge_flow;
+ bool fast_xmit;
+ bool hw_csum;
+ __be32 src_ip;
+ __be32 dest_ip;
+ bool ret;
+ u8 ttl;
+
+ /*
+ * Read the IP address from the iphdr, and set the src/dst ports to 0.
+ */
+ src_ip = iph->saddr;
+ dest_ip = iph->daddr;
+ rcu_read_lock();
+
+ /*
+ * Look for a connection match.
+ */
+#ifdef CONFIG_NF_FLOW_COOKIE
+ cm = si->sfe_flow_cookie_table[skb->flow_cookie & SFE_FLOW_COOKIE_MASK].match;
+ if (unlikely(!cm)) {
+ cm = sfe_ipv4_find_ipv4_connection_match_rcu(si, dev, IPPROTO_ESP, src_ip, 0, dest_ip, 0);
+ }
+#else
+ cm = sfe_ipv4_find_connection_match_rcu(si, dev, IPPROTO_ESP, src_ip, 0, dest_ip, 0);
+#endif
+ if (unlikely(!cm)) {
+ rcu_read_unlock();
+ sfe_ipv4_exception_stats_inc(si, SFE_IPV4_EXCEPTION_EVENT_ESP_NO_CONNECTION);
+ DEBUG_TRACE("no connection found for esp packet\n");
+ return 0;
+ }
+
+ /*
+ * Source interface validate.
+ */
+ if (unlikely((cm->flags & SFE_IPV4_CONNECTION_MATCH_FLAG_SRC_INTERFACE_CHECK) && (cm->match_dev != dev))) {
+ struct sfe_ipv4_connection *c = cm->connection;
+ int ret;
+
+ spin_lock_bh(&si->lock);
+ ret = sfe_ipv4_remove_connection(si, c);
+ spin_unlock_bh(&si->lock);
+
+ if (ret) {
+ sfe_ipv4_flush_connection(si, c, SFE_SYNC_REASON_FLUSH);
+ }
+ rcu_read_unlock();
+ sfe_ipv4_exception_stats_inc(si, SFE_IPV4_EXCEPTION_EVENT_INVALID_SRC_IFACE);
+ DEBUG_TRACE("flush on wrong source interface check failure\n");
+ return 0;
+ }
+
+ passthrough = cm->flags & SFE_IPV4_CONNECTION_MATCH_FLAG_PASSTHROUGH;
+ bridge_flow = !!(cm->flags & SFE_IPV4_CONNECTION_MATCH_FLAG_BRIDGE_FLOW);
+
+ /*
+ * If our packet has been marked as "sync on find" we can't actually
+ * forward it in the fast path, but now that we've found an associated
+ * connection we need sync its status before exception it to slow path unless
+ * it is passthrough (packets not directed to DUT) packet.
+ * TODO: revisit to ensure that pass through traffic is not bypassing firewall for fragmented cases
+ */
+ if (unlikely(sync_on_find) && !passthrough) {
+ sfe_ipv4_sync_status(si, cm->connection, SFE_SYNC_REASON_STATS);
+ rcu_read_unlock();
+ sfe_ipv4_exception_stats_inc(si, SFE_IPV4_EXCEPTION_EVENT_ESP_IP_OPTIONS_OR_INITIAL_FRAGMENT);
+ DEBUG_TRACE("%px: sfe: sync on find\n", cm);
+ return 0;
+ }
+
+ /*
+ * Check if skb was cloned. If it was, unshare it.
+ */
+ if (unlikely(skb_cloned(skb))) {
+ DEBUG_TRACE("%px: skb is a cloned skb\n", skb);
+ skb = skb_unshare(skb, GFP_ATOMIC);
+ if (!skb) {
+ DEBUG_WARN("Failed to unshare the cloned skb\n");
+ rcu_read_unlock();
+ return 0;
+ }
+
+ /*
+ * Update the iphdr pointer with the unshared skb's data area.
+ */
+ iph = (struct iphdr *)skb->data;
+ }
+
+ /*
+ * Enable HW csum if rx checksum is verified and xmit interface is CSUM offload capable.
+ */
+ hw_csum = !!(cm->flags & SFE_IPV4_CONNECTION_MATCH_FLAG_CSUM_OFFLOAD) && (skb->ip_summed == CHECKSUM_UNNECESSARY);
+
+ /*
+ * proto decap packet.
+ * Invoke the inet_protocol handler for delivery of the packet.
+ */
+ ipprot = rcu_dereference(cm->proto);
+ if (likely(ipprot)) {
+ skb_reset_network_header(skb);
+ skb_pull(skb, ihl);
+ skb_reset_transport_header(skb);
+ xmit_dev = cm->xmit_dev;
+ skb->dev = xmit_dev;
+
+ ret = ipprot->handler(skb);
+ if (ret) {
+ rcu_read_unlock();
+ this_cpu_inc(si->stats_pcpu->packets_not_forwarded64);
+ DEBUG_TRACE("ESP handler returned error %u\n", ret);
+ return 0;
+ }
+
+ /*
+ * Update traffic stats.
+ */
+ atomic_inc(&cm->rx_packet_count);
+ atomic_add(len, &cm->rx_byte_count);
+
+ rcu_read_unlock();
+ this_cpu_inc(si->stats_pcpu->packets_forwarded64);
+ return 1;
+ }
+
+ /*
+ * esp passthrough / ip local out scenarios.
+ */
+ /*
+ * If our packet is larger than the MTU of the transmit interface then
+ * we can't forward it easily.
+ */
+ if (unlikely(len > cm->xmit_dev_mtu)) {
+ sfe_ipv4_sync_status(si, cm->connection, SFE_SYNC_REASON_STATS);
+ rcu_read_unlock();
+ sfe_ipv4_exception_stats_inc(si, SFE_IPV4_EXCEPTION_EVENT_ESP_NEEDS_FRAGMENTATION);
+ DEBUG_TRACE("%px: sfe: larger than MTU\n", cm);
+ return 0;
+ }
+
+ /*
+ * need to ensure that TTL is >=2.
+ */
+ ttl = iph->ttl;
+ if (!bridge_flow && (ttl < 2) && passthrough) {
+ sfe_ipv4_sync_status(si, cm->connection, SFE_SYNC_REASON_STATS);
+ rcu_read_unlock();
+
+ DEBUG_TRACE("%px: sfe: TTL too low\n", skb);
+ sfe_ipv4_exception_stats_inc(si, SFE_IPV4_EXCEPTION_EVENT_ESP_SMALL_TTL);
+ return 0;
+ }
+
+ /*
+ * decrement TTL by 1.
+ */
+ iph->ttl = (ttl - (u8)(!bridge_flow && !tun_outer));
+
+ /*
+ * Update DSCP
+ */
+ if (unlikely(cm->flags & SFE_IPV4_CONNECTION_MATCH_FLAG_DSCP_REMARK)) {
+ iph->tos = (iph->tos & SFE_IPV4_DSCP_MASK) | cm->dscp;
+ }
+
+ /*
+ * Replace the IP checksum.
+ */
+ if (likely(hw_csum)) {
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ } else {
+ iph->check = sfe_ipv4_gen_ip_csum(iph);
+ }
+
+ /*
+ * Update traffic stats.
+ */
+ atomic_inc(&cm->rx_packet_count);
+ atomic_add(len, &cm->rx_byte_count);
+
+ xmit_dev = cm->xmit_dev;
+ skb->dev = xmit_dev;
+
+ /*
+ * write the layer - 2 header.
+ */
+ if (likely(cm->flags & SFE_IPV4_CONNECTION_MATCH_FLAG_WRITE_L2_HDR)) {
+ if (unlikely(!(cm->flags & SFE_IPV4_CONNECTION_MATCH_FLAG_WRITE_FAST_ETH_HDR))) {
+ dev_hard_header(skb, xmit_dev, ETH_P_IP, cm->xmit_dest_mac, cm->xmit_src_mac, len);
+ } else {
+ /*
+ * For the simple case we write this really fast.
+ */
+ struct ethhdr *eth = (struct ethhdr *)__skb_push(skb, ETH_HLEN);
+ eth->h_proto = htons(ETH_P_IP);
+ ether_addr_copy((u8 *)eth->h_dest, (u8 *)cm->xmit_dest_mac);
+ ether_addr_copy((u8 *)eth->h_source, (u8 *)cm->xmit_src_mac);
+ }
+ }
+
+ /*
+ * Update priority of skb
+ */
+ if (unlikely(cm->flags & SFE_IPV4_CONNECTION_MATCH_FLAG_PRIORITY_REMARK)) {
+ skb->priority = cm->priority;
+ }
+
+ /*
+ * Mark outgoing packet.
+ */
+ if (unlikely(cm->flags & SFE_IPV4_CONNECTION_MATCH_FLAG_MARK)) {
+ skb->mark = cm->mark;
+ }
+
+ fast_xmit = !!(cm->flags & SFE_IPV4_CONNECTION_MATCH_FLAG_FAST_XMIT);
+
+ rcu_read_unlock();
+ this_cpu_inc(si->stats_pcpu->packets_forwarded64);
+ prefetch(skb_shinfo(skb));
+
+ /*
+ * We do per packet condition check before we could fast xmit the
+ * packet.
+ */
+ if (likely(fast_xmit && dev_fast_xmit(skb, xmit_dev, features))) {
+ this_cpu_inc(si->stats_pcpu->packets_fast_xmited64);
+ return 1;
+ }
+
+ /*
+ * Mark that this packet has been fast forwarded.
+ */
+ skb->fast_forwarded = 1;
+
+ dev_queue_xmit(skb);
+ return 1;
+}