Subject: [PATCH net-next v10 2/2] selftests: net: test PPPoE packets in gro.sh

From: Qingfang Deng <[email-masked]>
Date: Wed, 13 May 2026 09:33:49 +0800

Add PPPoE test-cases to the GRO selftest. Only run a subset of
common_tests to avoid changing the hardcoded L3 offsets everywhere.
Add a new "pppoe_sid" test case to verify that packets with different
PPPoE session IDs are correctly identified as separate flows and not
coalesced.

Signed-off-by: Qingfang Deng <[email-masked]>
---
v10: no changes
v9: https://lore.kernel.org/netdev/[email-masked]
 - fix buffer length in send_changed_pppoe_sid()
v8: https://lore.kernel.org/netdev/[email-masked]
 - add a new macro L2_HLEN_MAX for PPPoE
v7: https://lore.kernel.org/netdev/[email-masked]
 - Do not run all the tests for PPPoE
 - Add a new test for PPPoE
v6: https://lore.kernel.org/netdev/[email-masked]

 tools/testing/selftests/drivers/net/config |   2 +
 tools/testing/selftests/drivers/net/gro.py |  11 +++
 tools/testing/selftests/net/lib/gro.c      | 100 +++++++++++++++++----
 3 files changed, 97 insertions(+), 16 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/config b/tools/testing/selftests/drivers/net/config
index 2309109a94ec..617de8aaf551 100644
--- a/tools/testing/selftests/drivers/net/config
+++ b/tools/testing/selftests/drivers/net/config
@@ -10,5 +10,7 @@ CONFIG_NETCONSOLE_EXTENDED_LOG=y
 CONFIG_NETDEVSIM=m
 CONFIG_NET_SCH_ETF=m
 CONFIG_NET_SCH_FQ=m
+CONFIG_PPP=y
+CONFIG_PPPOE=y
 CONFIG_VLAN_8021Q=m
 CONFIG_XDP_SOCKETS=y
diff --git a/tools/testing/selftests/drivers/net/gro.py b/tools/testing/selftests/drivers/net/gro.py
index 5ffaa7bdbff4..fd158c775b1c 100755
--- a/tools/testing/selftests/drivers/net/gro.py
+++ b/tools/testing/selftests/drivers/net/gro.py
@@ -323,6 +323,12 @@ def _gro_variants():
         "ip_frag6", "ip_v6ext_same", "ip_v6ext_diff",
     ]
 
+    # Tests specific to PPPoE
+    pppoe_tests = [
+        "data_same", "data_lrg_sml", "data_sml_lrg", "data_lrg_1byte",
+        "data_burst", "pppoe_sid",
+    ]
+
     for mode in ["sw", "hw", "lro"]:
         for protocol in ["ipv4", "ipv6", "ipip", "ip6ip6"]:
             for test_name in common_tests:
@@ -335,6 +341,11 @@ def _gro_variants():
                 for test_name in ipv6_tests:
                     yield mode, protocol, test_name
 
+    for mode in ["sw"]:
+        for protocol in ["pppoev4", "pppoev6"]:
+            for test_name in pppoe_tests:
+                yield mode, protocol, test_name
+
 
 @ksft_variants(_gro_variants())
 def test(cfg, mode, protocol, test_name):
diff --git a/tools/testing/selftests/net/lib/gro.c b/tools/testing/selftests/net/lib/gro.c
index 11b16ae5f0e8..fa35dfc8e790 100644
--- a/tools/testing/selftests/net/lib/gro.c
+++ b/tools/testing/selftests/net/lib/gro.c
@@ -67,12 +67,14 @@
 #include <errno.h>
 #include <error.h>
 #include <getopt.h>
+#include <net/ethernet.h>
+#include <net/if.h>
 #include <linux/filter.h>
 #include <linux/if_packet.h>
+#include <linux/if_pppox.h>
 #include <linux/ipv6.h>
 #include <linux/net_tstamp.h>
-#include <net/ethernet.h>
-#include <net/if.h>
+#include <linux/ppp_defs.h>
 #include <netinet/in.h>
 #include <netinet/ip.h>
 #include <netinet/ip6.h>
@@ -102,6 +104,7 @@
 #define MAX_LARGE_PKT_CNT ((IP_MAXPACKET - (MAX_HDR_LEN - ETH_HLEN)) /	\
 			   (ASSUMED_MTU - (MAX_HDR_LEN - ETH_HLEN)))
 #define MIN_EXTHDR_SIZE 8
+#define L2_HLEN_MAX	(ETH_HLEN + PPPOE_SES_HLEN)
 #define EXT_PAYLOAD_1 "\x00\x00\x00\x00\x00\x00"
 #define EXT_PAYLOAD_2 "\x11\x11\x11\x11\x11\x11"
 
@@ -134,6 +137,7 @@ static int total_hdr_len = -1;
 static int ethhdr_proto = -1;
 static bool ipip;
 static bool ip6ip6;
+static bool pppoe;
 static uint64_t txtime_ns;
 static int num_flows = 4;
 static bool order_check;
@@ -171,6 +175,22 @@ static void vlog(const char *fmt, ...)
 	}
 }
 
+static void fill_pppoelayer(void *buf, int payload_len, uint16_t sid)
+{
+	struct pppoe_ppp_hdr {
+		struct pppoe_hdr eh;
+		__be16 proto;
+	} *ph = buf;
+
+	payload_len += sizeof(struct tcphdr);
+	ph->eh.type = 1;
+	ph->eh.ver = 1;
+	ph->eh.code = 0;
+	ph->eh.sid = htons(sid);
+	ph->eh.length = htons(payload_len + sizeof(ph->proto));
+	ph->proto = htons(proto == PF_INET ? PPP_IP : PPP_IPV6);
+}
+
 static void setup_sock_filter(int fd)
 {
 	const int dport_off = tcp_offset + offsetof(struct tcphdr, dest);
@@ -412,11 +432,15 @@ static void create_packet(void *buf, int seq_offset, int ack_offset,
 
 	fill_networklayer(buf + inner_ip_off, payload_len, IPPROTO_TCP);
 	if (inner_ip_off > ETH_HLEN) {
-		int encap_proto = (proto == PF_INET) ?
-				  IPPROTO_IPIP : IPPROTO_IPV6;
+		if (pppoe) {
+			fill_pppoelayer(buf + ETH_HLEN, payload_len + ip_hdr_len, 0x1234);
+		} else {
+			int encap_proto = (proto == PF_INET) ?
+					  IPPROTO_IPIP : IPPROTO_IPV6;
 
-		fill_networklayer(buf + ETH_HLEN,
-				  payload_len + ip_hdr_len, encap_proto);
+			fill_networklayer(buf + ETH_HLEN,
+					  payload_len + ip_hdr_len, encap_proto);
+		}
 	}
 
 	fill_datalinklayer(buf);
@@ -526,7 +550,7 @@ static void send_flags(int fd, struct sockaddr_ll *daddr, int psh, int syn,
 static void send_data_pkts(int fd, struct sockaddr_ll *daddr,
 			   int payload_len1, int payload_len2)
 {
-	static char buf[ETH_HLEN + IP_MAXPACKET];
+	static char buf[L2_HLEN_MAX + IP_MAXPACKET];
 
 	create_packet(buf, 0, 0, payload_len1, 0);
 	write_packet(fd, buf, total_hdr_len + payload_len1, daddr);
@@ -1071,6 +1095,20 @@ static void send_fragment6(int fd, struct sockaddr_ll *daddr)
 	write_packet(fd, buf, bufpkt_len, daddr);
 }
 
+static void send_changed_pppoe_sid(int fd, struct sockaddr_ll *daddr)
+{
+	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+	int pkt_size = total_hdr_len + PAYLOAD_LEN;
+	struct pppoe_hdr *hdr = (struct pppoe_hdr *)(buf + ETH_HLEN);
+
+	create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+	write_packet(fd, buf, pkt_size, daddr);
+
+	create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+	hdr->sid = htons(0x4321);
+	write_packet(fd, buf, pkt_size, daddr);
+}
+
 static void bind_packetsocket(int fd)
 {
 	struct sockaddr_ll daddr = {};
@@ -1121,9 +1159,10 @@ static void recv_error(int fd, int rcv_errno)
 static void check_recv_pkts(int fd, int *correct_payload,
 			    int correct_num_pkts)
 {
-	static char buffer[IP_MAXPACKET + ETH_HLEN + 1];
-	struct iphdr *iph = (struct iphdr *)(buffer + ETH_HLEN);
-	struct ipv6hdr *ip6h = (struct ipv6hdr *)(buffer + ETH_HLEN);
+	static char buffer[IP_MAXPACKET + L2_HLEN_MAX + 1];
+	int nhoff = ETH_HLEN + (pppoe ? PPPOE_SES_HLEN : 0);
+	struct iphdr *iph = (struct iphdr *)(buffer + nhoff);
+	struct ipv6hdr *ip6h = (struct ipv6hdr *)(buffer + nhoff);
 	struct tcphdr *tcph;
 	bool bad_packet = false;
 	int tcp_ext_len = 0;
@@ -1140,7 +1179,7 @@ static void check_recv_pkts(int fd, int *correct_payload,
 
 	while (1) {
 		ip_ext_len = 0;
-		pkt_size = recv(fd, buffer, IP_MAXPACKET + ETH_HLEN + 1, 0);
+		pkt_size = recv(fd, buffer, sizeof(buffer), 0);
 		if (pkt_size < 0)
 			recv_error(fd, errno);
 
@@ -1183,9 +1222,10 @@ static void check_recv_pkts(int fd, int *correct_payload,
 
 static void check_capacity_pkts(int fd)
 {
-	static char buffer[IP_MAXPACKET + ETH_HLEN + 1];
-	struct iphdr *iph = (struct iphdr *)(buffer + ETH_HLEN);
-	struct ipv6hdr *ip6h = (struct ipv6hdr *)(buffer + ETH_HLEN);
+	static char buffer[IP_MAXPACKET + L2_HLEN_MAX + 1];
+	int nhoff = ETH_HLEN + (pppoe ? PPPOE_SES_HLEN : 0);
+	struct iphdr *iph = (struct iphdr *)(buffer + nhoff);
+	struct ipv6hdr *ip6h = (struct ipv6hdr *)(buffer + nhoff);
 	int num_pkt = 0, num_coal = 0, pkt_idx;
 	const char *fail_reason = NULL;
 	int flow_order[num_flows * 2];
@@ -1203,7 +1243,7 @@ static void check_capacity_pkts(int fd)
 
 	while (1) {
 		ip_ext_len = 0;
-		pkt_size = recv(fd, buffer, IP_MAXPACKET + ETH_HLEN + 1, 0);
+		pkt_size = recv(fd, buffer, sizeof(buffer), 0);
 		if (pkt_size < 0)
 			recv_error(fd, errno);
 
@@ -1499,6 +1539,12 @@ static void gro_sender(void)
 		usleep(fin_delay_us);
 		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
 
+	/* PPPoE sub-tests */
+	} else if (strcmp(testname, "pppoe_sid") == 0) {
+		send_changed_pppoe_sid(txfd, &daddr);
+		usleep(fin_delay_us);
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
 	} else {
 		error(1, 0, "Unknown testcase: %s", testname);
 	}
@@ -1716,6 +1762,12 @@ static void gro_receiver(void)
 	} else if (strcmp(testname, "capacity") == 0) {
 		check_capacity_pkts(rxfd);
 
+	} else if (strcmp(testname, "pppoe_sid") == 0) {
+		correct_payload[0] = PAYLOAD_LEN;
+		correct_payload[1] = PAYLOAD_LEN;
+		printf("different PPPoE session ID doesn't coalesce: ");
+		check_recv_pkts(rxfd, correct_payload, 2);
+
 	} else {
 		error(1, 0, "Test case error: unknown testname %s", testname);
 	}
@@ -1734,6 +1786,8 @@ static void parse_args(int argc, char **argv)
 		{ "ipv6", no_argument, NULL, '6' },
 		{ "ipip", no_argument, NULL, 'e' },
 		{ "ip6ip6", no_argument, NULL, 'E' },
+		{ "pppoev4", no_argument, NULL, 'p' },
+		{ "pppoev6", no_argument, NULL, 'P' },
 		{ "num-flows", required_argument, NULL, 'n' },
 		{ "rx", no_argument, NULL, 'r' },
 		{ "saddr", required_argument, NULL, 's' },
@@ -1745,7 +1799,7 @@ static void parse_args(int argc, char **argv)
 	};
 	int c;
 
-	while ((c = getopt_long(argc, argv, "46d:D:eEi:n:rs:S:t:ov", opts, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "46d:D:eEi:n:pPrs:S:t:ov", opts, NULL)) != -1) {
 		switch (c) {
 		case '4':
 			proto = PF_INET;
@@ -1765,6 +1819,16 @@ static void parse_args(int argc, char **argv)
 			proto = PF_INET6;
 			ethhdr_proto = htons(ETH_P_IPV6);
 			break;
+		case 'p':
+			pppoe = true;
+			proto = PF_INET;
+			ethhdr_proto = htons(ETH_P_PPP_SES);
+			break;
+		case 'P':
+			pppoe = true;
+			proto = PF_INET6;
+			ethhdr_proto = htons(ETH_P_PPP_SES);
+			break;
 		case 'd':
 			addr4_dst = addr6_dst = optarg;
 			break;
@@ -1812,6 +1876,10 @@ int main(int argc, char **argv)
 	} else if (ip6ip6) {
 		tcp_offset = ETH_HLEN + sizeof(struct ipv6hdr) * 2;
 		total_hdr_len = tcp_offset + sizeof(struct tcphdr);
+	} else if (pppoe) {
+		tcp_offset = ETH_HLEN + PPPOE_SES_HLEN +
+			(proto == PF_INET ? sizeof(struct iphdr) : sizeof(struct ipv6hdr));
+		total_hdr_len = tcp_offset + sizeof(struct tcphdr);
 	} else if (proto == PF_INET) {
 		tcp_offset = ETH_HLEN + sizeof(struct iphdr);
 		total_hdr_len = tcp_offset + sizeof(struct tcphdr);
-- 
2.43.0