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Message-Id: <20220111000001.3118189-2-quic_twear@quicinc.com>
Date: Mon, 10 Jan 2022 16:00:01 -0800
From: Tyler Wear <quic_twear@...cinc.com>
To: netdev@...r.kernel.org, bpf@...r.kernel.org
Cc: maze@...gle.com, yhs@...com, kafai@...com, toke@...hat.com,
daniel@...earbox.net, song@...nel.org,
Tyler Wear <quic_twear@...cinc.com>
Subject: [PATCH bpf-next v5 2/2] selftests/bpf: CGROUP_SKB test for skb_store_bytes()
Patch adds a test case to check that the source IP and Port of
packet are correctly changed for BPF_PROG_TYPE_CGROUP_SKB via
skb_store_bytes().
Test creates a client and server and checks that the packet
received on the server has the updated source IP and Port
that the bpf program modifies.
Signed-off-by: Tyler Wear <quic_twear@...cinc.com>
---
.../bpf/prog_tests/cgroup_store_bytes.c | 81 +++++++++++++++++++
.../selftests/bpf/progs/cgroup_store_bytes.c | 63 +++++++++++++++
2 files changed, 144 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/cgroup_store_bytes.c
create mode 100644 tools/testing/selftests/bpf/progs/cgroup_store_bytes.c
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_store_bytes.c b/tools/testing/selftests/bpf/prog_tests/cgroup_store_bytes.c
new file mode 100644
index 000000000000..f492fdb2f31b
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_store_bytes.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <test_progs.h>
+#include <network_helpers.h>
+
+#include "cgroup_store_bytes.skel.h"
+
+static int duration;
+
+void test_cgroup_store_bytes(void)
+{
+ int server_fd, cgroup_fd, client_fd;
+ struct sockaddr server_addr;
+ socklen_t addrlen = sizeof(server_addr);
+ char buf[] = "testing";
+ struct sockaddr_storage ss;
+ char recv_buf[BUFSIZ];
+ socklen_t slen;
+ struct in_addr addr;
+ unsigned short port;
+ struct cgroup_store_bytes *skel;
+
+ cgroup_fd = test__join_cgroup("/cgroup_store_bytes");
+ if (!ASSERT_GE(cgroup_fd, 0, "cgroup_fd"))
+ return;
+
+ skel = cgroup_store_bytes__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel"))
+ goto close_cgroup_fd;
+ if (!ASSERT_OK_PTR(skel->bss, "check_bss"))
+ goto close_cgroup_fd;
+
+ skel->links.cgroup_store_bytes = bpf_program__attach_cgroup(
+ skel->progs.cgroup_store_bytes, cgroup_fd);
+ if (!ASSERT_OK_PTR(skel, "cgroup_store_bytes"))
+ goto close_skeleton;
+
+ server_fd = start_server(AF_INET, SOCK_DGRAM, NULL, 0, 0);
+ if (!ASSERT_GE(server_fd, 0, "server_fd"))
+ goto close_cgroup_fd;
+
+ client_fd = start_server(AF_INET, SOCK_DGRAM, NULL, 0, 0);
+ if (!ASSERT_GE(client_fd, 0, "client_fd"))
+ goto close_server_fd;
+
+ if (getsockname(server_fd, &server_addr, &addrlen)) {
+ perror("Failed to get server addr");
+ goto close_client_fd;
+ }
+
+ if (CHECK_FAIL(sendto(client_fd, buf, sizeof(buf), 0, &server_addr,
+ sizeof(server_addr)) != sizeof(buf))) {
+ perror("Can't write on client");
+ goto close_client_fd;
+ }
+
+ if (recvfrom(server_fd, &recv_buf, sizeof(recv_buf), 0,
+ (struct sockaddr *)&ss, &slen) <= 0) {
+ perror("Recvfrom received no packets");
+ goto close_client_fd;
+ }
+
+ addr = ((struct sockaddr_in *)&ss)->sin_addr;
+
+ CHECK(addr.s_addr != 0xac100164, "bpf", "bpf program failed to change saddr");
+
+ port = ((struct sockaddr_in *)&ss)->sin_port;
+
+ CHECK(port != htons(5555), "bpf", "bpf program failed to change port");
+
+ CHECK(skel->bss->test_result != 1, "bpf", "bpf program returned failure");
+
+close_client_fd:
+ close(client_fd);
+close_server_fd:
+ close(server_fd);
+close_skeleton:
+ cgroup_store_bytes__destroy(skel);
+close_cgroup_fd:
+ close(cgroup_fd);
+}
diff --git a/tools/testing/selftests/bpf/progs/cgroup_store_bytes.c b/tools/testing/selftests/bpf/progs/cgroup_store_bytes.c
new file mode 100644
index 000000000000..d81d39281526
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/cgroup_store_bytes.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <errno.h>
+#include <linux/bpf.h>
+#include <linux/if_ether.h>
+#include <linux/ip.h>
+#include <netinet/in.h>
+#include <netinet/udp.h>
+#include <bpf/bpf_helpers.h>
+
+#define IP_SRC_OFF offsetof(struct iphdr, saddr)
+#define UDP_SPORT_OFF (sizeof(struct iphdr) + offsetof(struct udphdr, source))
+
+#define IS_PSEUDO 0x10
+
+#define UDP_CSUM_OFF (sizeof(struct iphdr) + offsetof(struct udphdr, check))
+#define IP_CSUM_OFF offsetof(struct iphdr, check)
+
+int test_result;
+
+SEC("cgroup_skb/egress")
+int cgroup_store_bytes(struct __sk_buff *skb)
+{
+ struct ethhdr eth;
+ struct iphdr iph;
+ struct udphdr udph;
+
+ __u32 map_key = 0;
+ __u32 test_passed = 0;
+
+ if (bpf_skb_load_bytes_relative(skb, 0, &iph, sizeof(iph),
+ BPF_HDR_START_NET))
+ goto fail;
+
+ if (bpf_skb_load_bytes_relative(skb, sizeof(iph), &udph, sizeof(udph),
+ BPF_HDR_START_NET))
+ goto fail;
+
+ __u32 old_ip = htonl(iph.saddr);
+ __u32 new_ip = 0xac100164; //172.16.1.100
+
+ bpf_l4_csum_replace(skb, UDP_CSUM_OFF, old_ip, new_ip,
+ IS_PSEUDO | sizeof(new_ip));
+ bpf_l3_csum_replace(skb, IP_CSUM_OFF, old_ip, new_ip, sizeof(new_ip));
+ if (bpf_skb_store_bytes(skb, IP_SRC_OFF, &new_ip, sizeof(new_ip), 0) < 0)
+ goto fail;
+
+ __u16 old_port = udph.source;
+ __u16 new_port = 5555;
+
+ bpf_l4_csum_replace(skb, UDP_CSUM_OFF, old_port, new_port,
+ IS_PSEUDO | sizeof(new_port));
+ if (bpf_skb_store_bytes(skb, UDP_SPORT_OFF, &new_port, sizeof(new_port),
+ 0) < 0)
+ goto fail;
+
+ test_passed = 1;
+
+fail:
+ test_result = test_passed;
+
+ return 1;
+}
--
2.25.1
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