From: Wesley Atwell <[email protected]>

Extend the tcp_ao repair selftests to exercise the legacy, v1, and
current TCP_REPAIR_WINDOW layouts, plus a synthesized retracted-window
image that preserves a larger historical right edge.

These tests validate both the append-only ABI contract and the restore-
time rebuilding of any snapshot state older userspace could not save.

Signed-off-by: Wesley Atwell <[email protected]>
---
 .../testing/selftests/net/tcp_ao/lib/aolib.h  |  83 +++++++-
 .../testing/selftests/net/tcp_ao/lib/repair.c |  18 +-
 .../selftests/net/tcp_ao/self-connect.c       | 201 +++++++++++++++++-
 3 files changed, 279 insertions(+), 23 deletions(-)

diff --git a/tools/testing/selftests/net/tcp_ao/lib/aolib.h 
b/tools/testing/selftests/net/tcp_ao/lib/aolib.h
index ebb2899c12fe..ef08db831457 100644
--- a/tools/testing/selftests/net/tcp_ao/lib/aolib.h
+++ b/tools/testing/selftests/net/tcp_ao/lib/aolib.h
@@ -13,6 +13,7 @@
 #include <linux/snmp.h>
 #include <linux/tcp.h>
 #include <netinet/in.h>
+#include <stddef.h>
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stdlib.h>
@@ -671,17 +672,55 @@ struct tcp_sock_state {
        int timestamp;
 };
 
-extern void __test_sock_checkpoint(int sk, struct tcp_sock_state *state,
-                                  void *addr, size_t addr_size);
+/* Legacy userspace stops before the snapshot field and therefore exercises
+ * the kernel's unknown-snapshot fallback path.
+ */
+static inline socklen_t test_tcp_repair_window_legacy_size(void)
+{
+       return offsetof(struct tcp_repair_window, rcv_wnd_scaling_ratio);
+}
+
+static inline socklen_t test_tcp_repair_window_v1_size(void)
+{
+       return offsetof(struct tcp_repair_window, rcv_mwnd_seq);
+}
+
+static inline socklen_t test_tcp_repair_window_exact_size(void)
+{
+       return sizeof(struct tcp_repair_window);
+}
+
+void __test_sock_checkpoint_opt(int sk, struct tcp_sock_state *state,
+                               socklen_t trw_len,
+                               void *addr, size_t addr_size);
 static inline void test_sock_checkpoint(int sk, struct tcp_sock_state *state,
                                        sockaddr_af *saddr)
 {
-       __test_sock_checkpoint(sk, state, saddr, sizeof(*saddr));
+       __test_sock_checkpoint_opt(sk, state, 
test_tcp_repair_window_exact_size(),
+                                  saddr, sizeof(*saddr));
+}
+
+static inline void test_sock_checkpoint_legacy(int sk,
+                                              struct tcp_sock_state *state,
+                                              sockaddr_af *saddr)
+{
+       __test_sock_checkpoint_opt(sk, state, 
test_tcp_repair_window_legacy_size(),
+                                  saddr, sizeof(*saddr));
+}
+
+static inline void test_sock_checkpoint_v1(int sk,
+                                          struct tcp_sock_state *state,
+                                          sockaddr_af *saddr)
+{
+       __test_sock_checkpoint_opt(sk, state, test_tcp_repair_window_v1_size(),
+                                  saddr, sizeof(*saddr));
 }
 extern void test_ao_checkpoint(int sk, struct tcp_ao_repair *state);
-extern void __test_sock_restore(int sk, const char *device,
-                               struct tcp_sock_state *state,
-                               void *saddr, void *daddr, size_t addr_size);
+void __test_sock_restore_opt(int sk, const char *device,
+                            struct tcp_sock_state *state,
+                            socklen_t trw_len,
+                            void *saddr, void *daddr,
+                            size_t addr_size);
 static inline void test_sock_restore(int sk, struct tcp_sock_state *state,
                                     sockaddr_af *saddr,
                                     const union tcp_addr daddr,
@@ -690,7 +729,37 @@ static inline void test_sock_restore(int sk, struct 
tcp_sock_state *state,
        sockaddr_af addr;
 
        tcp_addr_to_sockaddr_in(&addr, &daddr, htons(dport));
-       __test_sock_restore(sk, veth_name, state, saddr, &addr, sizeof(addr));
+       __test_sock_restore_opt(sk, veth_name, state,
+                               test_tcp_repair_window_exact_size(),
+                               saddr, &addr, sizeof(addr));
+}
+
+static inline void test_sock_restore_legacy(int sk,
+                                           struct tcp_sock_state *state,
+                                           sockaddr_af *saddr,
+                                           const union tcp_addr daddr,
+                                           unsigned int dport)
+{
+       sockaddr_af addr;
+
+       tcp_addr_to_sockaddr_in(&addr, &daddr, htons(dport));
+       __test_sock_restore_opt(sk, veth_name, state,
+                               test_tcp_repair_window_legacy_size(),
+                               saddr, &addr, sizeof(addr));
+}
+
+static inline void test_sock_restore_v1(int sk,
+                                       struct tcp_sock_state *state,
+                                       sockaddr_af *saddr,
+                                       const union tcp_addr daddr,
+                                       unsigned int dport)
+{
+       sockaddr_af addr;
+
+       tcp_addr_to_sockaddr_in(&addr, &daddr, htons(dport));
+       __test_sock_restore_opt(sk, veth_name, state,
+                               test_tcp_repair_window_v1_size(),
+                               saddr, &addr, sizeof(addr));
 }
 extern void test_ao_restore(int sk, struct tcp_ao_repair *state);
 extern void test_sock_state_free(struct tcp_sock_state *state);
diff --git a/tools/testing/selftests/net/tcp_ao/lib/repair.c 
b/tools/testing/selftests/net/tcp_ao/lib/repair.c
index 9893b3ba69f5..befbd0f72db5 100644
--- a/tools/testing/selftests/net/tcp_ao/lib/repair.c
+++ b/tools/testing/selftests/net/tcp_ao/lib/repair.c
@@ -66,8 +66,9 @@ static void test_sock_checkpoint_queue(int sk, int queue, int 
qlen,
                test_error("recv(%d): %d", qlen, ret);
 }
 
-void __test_sock_checkpoint(int sk, struct tcp_sock_state *state,
-                           void *addr, size_t addr_size)
+void __test_sock_checkpoint_opt(int sk, struct tcp_sock_state *state,
+                               socklen_t trw_len,
+                               void *addr, size_t addr_size)
 {
        socklen_t len = sizeof(state->info);
        int ret;
@@ -82,9 +83,9 @@ void __test_sock_checkpoint(int sk, struct tcp_sock_state 
*state,
        if (getsockname(sk, addr, &len) || len != addr_size)
                test_error("getsockname(): %d", (int)len);
 
-       len = sizeof(state->trw);
+       len = trw_len;
        ret = getsockopt(sk, SOL_TCP, TCP_REPAIR_WINDOW, &state->trw, &len);
-       if (ret || len != sizeof(state->trw))
+       if (ret || len != trw_len)
                test_error("getsockopt(TCP_REPAIR_WINDOW): %d", (int)len);
 
        if (ioctl(sk, SIOCOUTQ, &state->outq_len))
@@ -160,9 +161,10 @@ static void test_sock_restore_queue(int sk, int queue, 
void *buf, int len)
        } while (len > 0);
 }
 
-void __test_sock_restore(int sk, const char *device,
-                        struct tcp_sock_state *state,
-                        void *saddr, void *daddr, size_t addr_size)
+void __test_sock_restore_opt(int sk, const char *device,
+                            struct tcp_sock_state *state,
+                            socklen_t trw_len,
+                            void *saddr, void *daddr, size_t addr_size)
 {
        struct tcp_repair_opt opts[4];
        unsigned int opt_nr = 0;
@@ -215,7 +217,7 @@ void __test_sock_restore(int sk, const char *device,
        }
        test_sock_restore_queue(sk, TCP_RECV_QUEUE, state->in.buf, 
state->inq_len);
        test_sock_restore_queue(sk, TCP_SEND_QUEUE, state->out.buf, 
state->outq_len);
-       if (setsockopt(sk, SOL_TCP, TCP_REPAIR_WINDOW, &state->trw, 
sizeof(state->trw)))
+       if (setsockopt(sk, SOL_TCP, TCP_REPAIR_WINDOW, &state->trw, trw_len))
                test_error("setsockopt(TCP_REPAIR_WINDOW)");
 }
 
diff --git a/tools/testing/selftests/net/tcp_ao/self-connect.c 
b/tools/testing/selftests/net/tcp_ao/self-connect.c
index 2c73bea698a6..a7c0f2edd351 100644
--- a/tools/testing/selftests/net/tcp_ao/self-connect.c
+++ b/tools/testing/selftests/net/tcp_ao/self-connect.c
@@ -4,6 +4,14 @@
 #include "aolib.h"
 
 static union tcp_addr local_addr;
+static bool checked_repair_window_lens;
+
+enum repair_window_mode {
+       REPAIR_WINDOW_CURRENT,
+       REPAIR_WINDOW_LEGACY,
+       REPAIR_WINDOW_V1,
+       REPAIR_WINDOW_RETRACTED,
+};
 
 static void __setup_lo_intf(const char *lo_intf,
                            const char *addr_str, uint8_t prefix)
@@ -30,8 +38,157 @@ static void setup_lo_intf(const char *lo_intf)
 #endif
 }
 
+/* The repair ABI accepts the legacy, v1, and current layouts. */
+static void test_repair_window_len_contract(int sk)
+{
+       struct tcp_repair_window trw = {};
+       socklen_t len = test_tcp_repair_window_exact_size();
+       socklen_t v1_len = test_tcp_repair_window_v1_size();
+       socklen_t bad_len = test_tcp_repair_window_legacy_size() + 1;
+       int ret;
+
+       if (checked_repair_window_lens)
+               return;
+
+       checked_repair_window_lens = true;
+
+       ret = getsockopt(sk, SOL_TCP, TCP_REPAIR_WINDOW, &trw, &len);
+       if (ret || len != test_tcp_repair_window_exact_size())
+               test_error("getsockopt(TCP_REPAIR_WINDOW): %d", (int)len);
+
+       len = v1_len;
+       ret = getsockopt(sk, SOL_TCP, TCP_REPAIR_WINDOW, &trw, &len);
+       if (ret || len != v1_len)
+               test_fail("repair-window get accepts v1 len");
+       else
+               test_ok("repair-window get accepts v1 len");
+
+       len = bad_len;
+       ret = getsockopt(sk, SOL_TCP, TCP_REPAIR_WINDOW, &trw, &len);
+       if (ret == 0 || errno != EINVAL)
+               test_fail("repair-window get rejects invalid len");
+       else
+               test_ok("repair-window get rejects invalid len");
+
+       ret = setsockopt(sk, SOL_TCP, TCP_REPAIR_WINDOW, &trw, bad_len);
+       if (ret == 0 || errno != EINVAL)
+               test_fail("repair-window set rejects invalid len");
+       else
+               test_ok("repair-window set rejects invalid len");
+
+       ret = setsockopt(sk, SOL_TCP, TCP_REPAIR_WINDOW, &trw, v1_len + 1);
+       if (ret == 0 || errno != EINVAL)
+               test_fail("repair-window set rejects invalid v1+1 len");
+       else
+               test_ok("repair-window set rejects invalid v1+1 len");
+}
+
+static void test_retracted_repair_window_state(int sk,
+                                              struct tcp_sock_state *img)
+{
+       struct tcp_repair_window trw = {};
+       socklen_t len = sizeof(trw);
+       int ret;
+
+       ret = getsockopt(sk, SOL_TCP, TCP_REPAIR_WINDOW, &trw, &len);
+       if (ret || len != sizeof(trw))
+               test_error("getsockopt(TCP_REPAIR_WINDOW): %d", (int)len);
+
+       if (trw.rcv_mwnd_seq != img->trw.rcv_mwnd_seq ||
+           trw.rcv_mwnd_scaling_ratio != img->trw.rcv_mwnd_scaling_ratio ||
+           trw.rcv_wnd != img->trw.rcv_wnd ||
+           trw.rcv_wup != img->trw.rcv_wup ||
+           trw.rcv_wnd_scaling_ratio != img->trw.rcv_wnd_scaling_ratio)
+               test_fail("repair-window restore preserves retracted state");
+       else
+               test_ok("repair-window restore preserves retracted state");
+}
+
+static void test_v1_repair_window_state(int sk, struct tcp_sock_state *img)
+{
+       struct tcp_repair_window trw = {};
+       socklen_t len = sizeof(trw);
+       __u32 max_right = img->trw.rcv_wup + img->trw.rcv_wnd;
+       int ret;
+
+       ret = getsockopt(sk, SOL_TCP, TCP_REPAIR_WINDOW, &trw, &len);
+       if (ret || len != sizeof(trw))
+               test_error("getsockopt(TCP_REPAIR_WINDOW): %d", (int)len);
+
+       if (trw.rcv_mwnd_seq != max_right ||
+           trw.rcv_mwnd_scaling_ratio != img->trw.rcv_wnd_scaling_ratio ||
+           trw.rcv_wnd != img->trw.rcv_wnd ||
+           trw.rcv_wup != img->trw.rcv_wup ||
+           trw.rcv_wnd_scaling_ratio != img->trw.rcv_wnd_scaling_ratio)
+               test_fail("repair-window v1 restore rebuilds max-window state");
+       else
+               test_ok("repair-window v1 restore rebuilds max-window state");
+}
+
+/* Synthesize a repair image whose live rwnd was retracted after a larger
+ * right edge had already been advertised, so restore testing can validate
+ * snapshot preservation without depending on the live receive path.
+ */
+static bool make_retracted_repair_window_state(struct tcp_sock_state *img)
+{
+       __u32 gran = 1U << img->info.tcpi_rcv_wscale;
+       __u32 max_right;
+       __u32 shrink;
+
+       if (!(img->info.tcpi_options & TCPI_OPT_WSCALE))
+               return false;
+
+       max_right = img->trw.rcv_wup + img->trw.rcv_wnd;
+       shrink = img->trw.rcv_wnd / 4;
+       if (shrink < gran)
+               shrink = gran;
+       if (shrink >= img->trw.rcv_wnd)
+               shrink = img->trw.rcv_wnd >> 1;
+       if (shrink == 0 || shrink >= img->trw.rcv_wnd)
+               return false;
+
+       img->trw.rcv_wnd -= shrink;
+       img->trw.rcv_mwnd_seq = max_right;
+       img->trw.rcv_mwnd_scaling_ratio = img->trw.rcv_wnd_scaling_ratio;
+       return true;
+}
+
+static socklen_t repair_window_len(enum repair_window_mode mode)
+{
+       switch (mode) {
+       case REPAIR_WINDOW_LEGACY:
+               return test_tcp_repair_window_legacy_size();
+       case REPAIR_WINDOW_V1:
+               return test_tcp_repair_window_v1_size();
+       case REPAIR_WINDOW_CURRENT:
+       case REPAIR_WINDOW_RETRACTED:
+               return test_tcp_repair_window_exact_size();
+       }
+
+       return test_tcp_repair_window_exact_size();
+}
+
+static void test_sock_checkpoint_mode(enum repair_window_mode mode, int sk,
+                                     struct tcp_sock_state *img,
+                                     sockaddr_af *addr)
+{
+       switch (mode) {
+       case REPAIR_WINDOW_LEGACY:
+               test_sock_checkpoint_legacy(sk, img, addr);
+               break;
+       case REPAIR_WINDOW_V1:
+               test_sock_checkpoint_v1(sk, img, addr);
+               break;
+       case REPAIR_WINDOW_CURRENT:
+       case REPAIR_WINDOW_RETRACTED:
+               test_sock_checkpoint(sk, img, addr);
+               break;
+       }
+}
+
 static void tcp_self_connect(const char *tst, unsigned int port,
-                            bool different_keyids, bool check_restore)
+                            bool different_keyids, bool check_restore,
+                            enum repair_window_mode repair_window_mode)
 {
        struct tcp_counters before, after;
        uint64_t before_aogood, after_aogood;
@@ -109,7 +266,16 @@ static void tcp_self_connect(const char *tst, unsigned int 
port,
        }
 
        test_enable_repair(sk);
-       test_sock_checkpoint(sk, &img, &addr);
+       test_repair_window_len_contract(sk);
+       test_sock_checkpoint_mode(repair_window_mode, sk, &img, &addr);
+       if (repair_window_mode == REPAIR_WINDOW_RETRACTED &&
+           !make_retracted_repair_window_state(&img)) {
+               test_sock_state_free(&img);
+               netstat_free(ns_before);
+               close(sk);
+               test_skip("%s: no scaled repair window to retract", tst);
+               return;
+       }
 #ifdef IPV6_TEST
        addr.sin6_port = htons(port + 1);
 #else
@@ -123,7 +289,9 @@ static void tcp_self_connect(const char *tst, unsigned int 
port,
                test_error("socket()");
 
        test_enable_repair(sk);
-       __test_sock_restore(sk, "lo", &img, &addr, &addr, sizeof(addr));
+       __test_sock_restore_opt(sk, "lo", &img,
+                               repair_window_len(repair_window_mode),
+                               &addr, &addr, sizeof(addr));
        if (different_keyids) {
                if (test_add_repaired_key(sk, DEFAULT_TEST_PASSWORD, 0,
                                          local_addr, -1, 7, 5))
@@ -137,6 +305,10 @@ static void tcp_self_connect(const char *tst, unsigned int 
port,
                        test_error("setsockopt(TCP_AO_ADD_KEY)");
        }
        test_ao_restore(sk, &ao_img);
+       if (repair_window_mode == REPAIR_WINDOW_V1)
+               test_v1_repair_window_state(sk, &img);
+       if (repair_window_mode == REPAIR_WINDOW_RETRACTED)
+               test_retracted_repair_window_state(sk, &img);
        test_disable_repair(sk);
        test_sock_state_free(&img);
        if (test_client_verify(sk, 100, nr_packets)) {
@@ -165,20 +337,33 @@ static void *client_fn(void *arg)
 
        setup_lo_intf("lo");
 
-       tcp_self_connect("self-connect(same keyids)", port++, false, false);
+       tcp_self_connect("self-connect(same keyids)", port++, false, false,
+                        REPAIR_WINDOW_CURRENT);
 
        /* expecting rnext to change based on the first segment RNext != 
Current */
        trace_ao_event_expect(TCP_AO_RNEXT_REQUEST, local_addr, local_addr,
                              port, port, 0, -1, -1, -1, -1, -1, 7, 5, -1);
-       tcp_self_connect("self-connect(different keyids)", port++, true, false);
-       tcp_self_connect("self-connect(restore)", port, false, true);
+       tcp_self_connect("self-connect(different keyids)", port++, true, false,
+                        REPAIR_WINDOW_CURRENT);
+       tcp_self_connect("self-connect(restore)", port, false, true,
+                        REPAIR_WINDOW_CURRENT);
+       port += 2; /* restore test restores over different port */
+       tcp_self_connect("self-connect(restore, legacy repair window)", port,
+                        false, true, REPAIR_WINDOW_LEGACY);
+       port += 2; /* restore test restores over different port */
+       tcp_self_connect("self-connect(restore, v1 repair window)", port,
+                        false, true, REPAIR_WINDOW_V1);
+       port += 2; /* restore test restores over different port */
+       tcp_self_connect("self-connect(restore, retracted repair window)", port,
+                        false, true, REPAIR_WINDOW_RETRACTED);
        port += 2; /* restore test restores over different port */
        trace_ao_event_expect(TCP_AO_RNEXT_REQUEST, local_addr, local_addr,
                              port, port, 0, -1, -1, -1, -1, -1, 7, 5, -1);
        /* intentionally on restore they are added to the socket in different 
order */
        trace_ao_event_expect(TCP_AO_RNEXT_REQUEST, local_addr, local_addr,
                              port + 1, port + 1, 0, -1, -1, -1, -1, -1, 5, 7, 
-1);
-       tcp_self_connect("self-connect(restore, different keyids)", port, true, 
true);
+       tcp_self_connect("self-connect(restore, different keyids)",
+                        port, true, true, REPAIR_WINDOW_CURRENT);
        port += 2; /* restore test restores over different port */
 
        return NULL;
@@ -186,6 +371,6 @@ static void *client_fn(void *arg)
 
 int main(int argc, char *argv[])
 {
-       test_init(5, client_fn, NULL);
+       test_init(14, client_fn, NULL);
        return 0;
 }
-- 
2.43.0


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