xdp-bench: Add parse-ip packet operation to basic actions

Add a 'parse-ip' packet operation to the basic actions (for drop, pass and
tx commands). This will parse the packet all the way down to the IP header
instead of just touching a single field in the ethernet header like the
'touch' operation does.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>

xdp-bench/README.org

@@ -66,6 +66,7 @@ following actions are available:
 #+begin_src sh
  no-touch		- Drop the packet without touching the packet data
  touch		- Read a field in the packet header before dropping
+ parse-ip		- Parse the IP header field before dropping
  swap-macs		- Swap the source and destination MAC addresses before dropping
 #+end_src
 
@@ -130,6 +131,7 @@ following actions are available:
 #+begin_src sh
  no-touch		- Pass the packet without touching the packet data
  touch		- Read a field in the packet header before passing
+ parse-ip		- Parse the IP header field before passing
  swap-macs		- Swap the source and destination MAC addresses before passing
 #+end_src
 
@@ -189,6 +191,7 @@ following actions are available:
 #+begin_src sh
  no-touch		- Transmit the packet without touching the packet data
  touch		- Read a field in the packet header before transmitting
+ parse-ip		- Parse the IP header field before transmitting
  swap-macs		- Swap the source and destination MAC addresses before transmitting
 #+end_src
 

xdp-bench/tests/test-xdp-bench.sh

@@ -9,6 +9,7 @@ test_basic()
     export XDP_SAMPLE_IMMEDIATE_EXIT=1
     check_run $XDP_BENCH $action $NS -vv
     check_run $XDP_BENCH $action $NS -p read-data -vv
+    check_run $XDP_BENCH $action $NS -p parse-ip -vv
     check_run $XDP_BENCH $action $NS -p swap-macs -vv
     check_run $XDP_BENCH $action $NS -m skb -vv
     check_run $XDP_BENCH $action $NS -e -vv

xdp-bench/xdp-bench.8

@@ -75,6 +75,7 @@ following actions are available:
 .nf
 \fCno-touch		- Drop the packet without touching the packet data
 touch		- Read a field in the packet header before dropping
+parse-ip		- Parse the IP header field before dropping
 swap-macs		- Swap the source and destination MAC addresses before dropping
 \fP
 .fi
@@ -157,6 +158,7 @@ following actions are available:
 .nf
 \fCno-touch		- Pass the packet without touching the packet data
 touch		- Read a field in the packet header before passing
+parse-ip		- Parse the IP header field before passing
 swap-macs		- Swap the source and destination MAC addresses before passing
 \fP
 .fi
@@ -233,6 +235,7 @@ following actions are available:
 .nf
 \fCno-touch		- Transmit the packet without touching the packet data
 touch		- Read a field in the packet header before transmitting
+parse-ip		- Parse the IP header field before transmitting
 swap-macs		- Swap the source and destination MAC addresses before transmitting
 \fP
 .fi

xdp-bench/xdp-bench.c

@@ -37,6 +37,7 @@ struct enum_val xdp_modes[] = {
 struct enum_val basic_program_modes[] = {
        {"no-touch", BASIC_NO_TOUCH},
        {"read-data", BASIC_READ_DATA},
+       {"parse-ip", BASIC_PARSE_IPHDR},
        {"swap-macs", BASIC_SWAP_MACS},
        {NULL, 0}
 };

xdp-bench/xdp_basic.bpf.c

@@ -22,6 +22,33 @@ const volatile enum basic_program_mode prog_mode = BASIC_NO_TOUCH;
 const volatile bool rxq_stats = 0;
 const volatile enum xdp_action action = XDP_DROP;
 
+static int parse_ip_header(struct xdp_md *ctx)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data = (void *)(long)ctx->data;
+	struct hdr_cursor nh = { .pos = data };
+	struct ipv6hdr *ipv6hdr;
+	struct iphdr *iphdr;
+	struct ethhdr *eth;
+	int eth_type, ip_type;
+
+	eth_type = parse_ethhdr(&nh, data_end, &eth);
+	if (eth_type < 0)
+		return eth_type;
+
+	if (eth_type == bpf_htons(ETH_P_IP)) {
+		ip_type = parse_iphdr(&nh, data_end, &iphdr);
+		if (ip_type < 0)
+			return ip_type;
+	} else if (eth_type == bpf_htons(ETH_P_IPV6)) {
+		ip_type = parse_ip6hdr(&nh, data_end, &ipv6hdr);
+		if (ip_type < 0)
+			return ip_type;
+	}
+
+	return 0;
+}
+
 SEC("xdp")
 int xdp_basic_prog(struct xdp_md *ctx)
 {
@@ -54,6 +81,10 @@ int xdp_basic_prog(struct xdp_md *ctx)
 		if (bpf_ntohs(eth->h_proto) < ETH_P_802_3_MIN)
 			return XDP_ABORTED;
 		break;
+	case BASIC_PARSE_IPHDR:
+		if (parse_ip_header(ctx))
+			return XDP_ABORTED;
+		break;
 	case BASIC_SWAP_MACS:
 		swap_src_dst_mac(data);
 		break;