[PATCH] ipa: Change ipa_msg_recv() to support partial receive

Currently ipa_msg_recv() fails, when messages are received partially. This patch provides a new function ipa_msg_recv_buffered() that uses an additional ** to a message buffer to store partial data. When this happens, -EAGAIN is returned. If NULL is used, the function behaves similar to ipa_msg_recv() and fails on partial read. In addition in case of errors the return value is now always -EXXX and the contents of errno is undefined. Note that this feature needs support by the calling code insofar that *tmp_msg must be set to NULL initially and it must be freed and set to NULL manually when the socket is closed. Note also that ipa_msg_recv() is then a wrapper around ipa_msg_recv_buffered() which mimics the old error behaviour by setting errno explicitely to -rc and returning -1 when an error has happened. Ticket: OW#728 Sponsored-by: On-Waves ehf --- TODO-RELEASE | 1 + include/osmocom/abis/e1_input.h | 2 + include/osmocom/abis/ipa.h | 3 + src/input/ipa.c | 151 ++++++++++++++++++++++++++++++--------- src/input/ipaccess.c | 13 +++- tests/ipa_recv/ipa_recv_test.c | 55 +++++++++----- tests/ipa_recv/ipa_recv_test.ok | 27 ++++++- 7 files changed, 198 insertions(+), 54 deletions(-) diff --git a/TODO-RELEASE b/TODO-RELEASE index 43b1e8e..71931db 100644 --- a/TODO-RELEASE +++ b/TODO-RELEASE @@ -1 +1,2 @@ #library what description / commit summary line +libosmoabis abi-change ipa: Change ipa_msg_recv() to support partial receive diff --git a/include/osmocom/abis/e1_input.h b/include/osmocom/abis/e1_input.h index 9b77893..cf8677b 100644 --- a/include/osmocom/abis/e1_input.h +++ b/include/osmocom/abis/e1_input.h @@ -109,6 +109,8 @@ struct e1inp_ts { struct osmo_fd fd; } rs232; } driver; + + struct msgb *pending_msg; }; struct gsm_e1_subslot { diff --git a/include/osmocom/abis/ipa.h b/include/osmocom/abis/ipa.h index d577d74..982b694 100644 --- a/include/osmocom/abis/ipa.h +++ b/include/osmocom/abis/ipa.h @@ -27,6 +27,7 @@ struct ipa_server_conn { int (*closed_cb)(struct ipa_server_conn *peer); int (*cb)(struct ipa_server_conn *peer, struct msgb *msg); void *data; + struct msgb *pending_msg; }; struct ipa_server_conn *ipa_server_conn_create(void *ctx, struct ipa_server_link *link, int fd, int (*cb)(struct ipa_server_conn *peer, struct msgb *msg), int (*closed_cb)(struct ipa_server_conn *peer), void *data); @@ -53,6 +54,7 @@ struct ipa_client_conn { int (*read_cb)(struct ipa_client_conn *link, struct msgb *msg); int (*write_cb)(struct ipa_client_conn *link); void *data; + struct msgb *pending_msg; }; struct ipa_client_conn *ipa_client_conn_create(void *ctx, struct e1inp_ts *ts, int priv_nr, const char *addr, uint16_t port, void (*updown)(struct ipa_client_conn *link, int), int (*read_cb)(struct ipa_client_conn *link, struct msgb *msgb), int (*write_cb)(struct ipa_client_conn *link), void *data); @@ -64,6 +66,7 @@ void ipa_client_conn_close(struct ipa_client_conn *link); void ipa_client_conn_send(struct ipa_client_conn *link, struct msgb *msg); int ipa_msg_recv(int fd, struct msgb **rmsg); +int ipa_msg_recv_buffered(int fd, struct msgb **rmsg, struct msgb **tmp_msg); int ipaccess_rcvmsg_base(struct msgb *msg, struct osmo_fd *bfd); diff --git a/src/input/ipa.c b/src/input/ipa.c index b5abd36..71e1227 100644 --- a/src/input/ipa.c +++ b/src/input/ipa.c @@ -49,50 +49,130 @@ void ipa_msg_push_header(struct msgb *msg, uint8_t proto) int ipa_msg_recv(int fd, struct msgb **rmsg) { - struct msgb *msg; + int rc = ipa_msg_recv_buffered(fd, rmsg, NULL); + if (rc < 0) { + errno = -rc; + rc = -1; + } + return rc; +} + +int ipa_msg_recv_buffered(int fd, struct msgb **rmsg, struct msgb **tmp_msg) +{ + struct msgb *msg = tmp_msg ? *tmp_msg : NULL; struct ipaccess_head *hh; int len, ret; + int needed; - msg = ipa_msg_alloc(0); if (msg == NULL) - return -ENOMEM; + msg = ipa_msg_alloc(0); - /* first read our 3-byte header */ - hh = (struct ipaccess_head *) msg->data; - ret = recv(fd, msg->data, sizeof(*hh), 0); - if (ret <= 0) { - msgb_free(msg); - return ret; - } else if (ret != sizeof(*hh)) { - LOGP(DLINP, LOGL_ERROR, "too small message received\n"); - msgb_free(msg); - return -EIO; + if (msg == NULL) { + ret = -ENOMEM; + goto discard_msg; } - msgb_put(msg, ret); + + if (msg->l2h == NULL) { + /* first read our 3-byte header */ + needed = sizeof(*hh) - msg->len; + ret = recv(fd, msg->tail, needed, 0); + if (ret == 0) + goto discard_msg; + + if (ret < 0) { + if (errno == EAGAIN || errno == EINTR) + ret = 0; + else { + ret = -errno; + goto discard_msg; + } + } + + msgb_put(msg, ret); + + if (ret < needed) { + if (msg->len == 0) { + ret = -EAGAIN; + goto discard_msg; + } + + LOGP(DLINP, LOGL_INFO, + "Received part of IPA message header (%d/%d)\n", + msg->len, sizeof(*hh)); + if (!tmp_msg) { + ret = -EIO; + goto discard_msg; + } + *tmp_msg = msg; + return -EAGAIN; + } + + msg->l2h = msg->tail; + } + + hh = (struct ipaccess_head *) msg->data; /* then read the length as specified in header */ - msg->l2h = msg->data + sizeof(*hh); len = ntohs(hh->len); if (len < 0 || IPA_ALLOC_SIZE < len + sizeof(*hh)) { LOGP(DLINP, LOGL_ERROR, "bad message length of %d bytes, " - "received %d bytes\n", len, ret); - msgb_free(msg); - return -EIO; + "received %d bytes\n", len, msg->len); + ret = -EIO; + goto discard_msg; } - ret = recv(fd, msg->l2h, len, 0); - if (ret <= 0) { - msgb_free(msg); - return ret; - } else if (ret < len) { - LOGP(DLINP, LOGL_ERROR, "truncated message received\n"); - msgb_free(msg); - return -EIO; + needed = len - msgb_l2len(msg); + + if (needed > 0) { + ret = recv(fd, msg->tail, needed, 0); + + if (ret == 0) + goto discard_msg; + + if (ret < 0) { + if (errno == EAGAIN || errno == EINTR) + ret = 0; + else { + ret = -errno; + goto discard_msg; + } + } + + msgb_put(msg, ret); + + if (ret < needed) { + LOGP(DLINP, LOGL_INFO, + "Received part of IPA message L2 data (%d/%d)\n", + msgb_l2len(msg), len); + if (!tmp_msg) { + ret = -EIO; + goto discard_msg; + } + *tmp_msg = msg; + return -EAGAIN; + } } - msgb_put(msg, ret); + + ret = msgb_l2len(msg); + + if (ret == 0) { + LOGP(DLINP, LOGL_INFO, + "Discarding IPA message without payload\n"); + ret = -EAGAIN; + goto discard_msg; + } + + if (tmp_msg) + *tmp_msg = NULL; *rmsg = msg; return ret; + +discard_msg: + if (tmp_msg) + *tmp_msg = NULL; + msgb_free(msg); + return ret; } void ipa_client_conn_close(struct ipa_client_conn *link) @@ -103,6 +183,8 @@ void ipa_client_conn_close(struct ipa_client_conn *link) close(link->ofd->fd); link->ofd->fd = -1; } + msgb_free(link->pending_msg); + link->pending_msg = NULL; } static void ipa_client_read(struct ipa_client_conn *link) @@ -113,11 +195,12 @@ static void ipa_client_read(struct ipa_client_conn *link) LOGP(DLINP, LOGL_DEBUG, "message received\n"); - ret = ipa_msg_recv(ofd->fd, &msg); + ret = ipa_msg_recv_buffered(ofd->fd, &msg, &link->pending_msg); if (ret < 0) { - if (errno == EPIPE || errno == ECONNRESET) { + if (ret == -EAGAIN) + return; + if (ret == -EPIPE || ret == -ECONNRESET) LOGP(DLINP, LOGL_ERROR, "lost connection with server\n"); - } ipa_client_conn_close(link); if (link->updown_cb) link->updown_cb(link, 0); @@ -382,11 +465,12 @@ static void ipa_server_conn_read(struct ipa_server_conn *conn) LOGP(DLINP, LOGL_DEBUG, "message received\n"); - ret = ipa_msg_recv(ofd->fd, &msg); + ret = ipa_msg_recv_buffered(ofd->fd, &msg, &conn->pending_msg); if (ret < 0) { - if (errno == EPIPE || errno == ECONNRESET) { + if (ret == -EAGAIN) + return; + if (ret == -EPIPE || ret == -ECONNRESET) LOGP(DLINP, LOGL_ERROR, "lost connection with server\n"); - } ipa_server_conn_destroy(conn); return; } else if (ret == 0) { @@ -471,6 +555,7 @@ ipa_server_conn_create(void *ctx, struct ipa_server_link *link, int fd, void ipa_server_conn_destroy(struct ipa_server_conn *conn) { close(conn->ofd.fd); + msgb_free(conn->pending_msg); osmo_fd_unregister(&conn->ofd); if (conn->closed_cb) conn->closed_cb(conn); diff --git a/src/input/ipaccess.c b/src/input/ipaccess.c index 225d70c..7ac5ad1 100644 --- a/src/input/ipaccess.c +++ b/src/input/ipaccess.c @@ -258,6 +258,8 @@ int ipaccess_rcvmsg_bts_base(struct msgb *msg, static int ipaccess_drop(struct osmo_fd *bfd, struct e1inp_line *line) { int ret = 1; + unsigned int ts_nr = bfd->priv_nr; + struct e1inp_ts *e1i_ts = &line->ts[ts_nr-1]; /* Error case: we did not see any ID_RESP yet for this socket. */ if (bfd->fd != -1) { @@ -269,6 +271,9 @@ static int ipaccess_drop(struct osmo_fd *bfd, struct e1inp_line *line) ret = -ENOENT; } + msgb_free(e1i_ts->pending_msg); + e1i_ts->pending_msg = NULL; + /* e1inp_sign_link_destroy releases the socket descriptors for us. */ line->ops->sign_link_down(line); @@ -415,13 +420,15 @@ static int handle_ts1_read(struct osmo_fd *bfd) struct e1inp_ts *e1i_ts = &line->ts[ts_nr-1]; struct e1inp_sign_link *link; struct ipaccess_head *hh; - struct msgb *msg; + struct msgb *msg = NULL; int ret; - ret = ipa_msg_recv(bfd->fd, &msg); + ret = ipa_msg_recv_buffered(bfd->fd, &msg, &e1i_ts->pending_msg); if (ret < 0) { + if (ret == -EAGAIN) + return 0; LOGP(DLINP, LOGL_NOTICE, "Sign link problems, " - "closing socket. Reason: %s\n", strerror(errno)); + "closing socket. Reason: %s\n", strerror(-ret)); goto err; } else if (ret == 0) { LOGP(DLINP, LOGL_NOTICE, "Sign link vanished, dead socket\n"); diff --git a/tests/ipa_recv/ipa_recv_test.c b/tests/ipa_recv/ipa_recv_test.c index 7b26259..8cdc7e2 100644 --- a/tests/ipa_recv/ipa_recv_test.c +++ b/tests/ipa_recv/ipa_recv_test.c @@ -86,7 +86,7 @@ static void append_ipa_message(struct msgb *msg, int proto, const char *text) strcpy((char *)l2, text); } -static int receive_messages(int fd) +static int receive_messages(int fd, struct msgb **pending_msg) { struct msgb *msg; char dummy; @@ -97,13 +97,22 @@ static int receive_messages(int fd) break; } msg = NULL; - rc = ipa_msg_recv(fd, &msg); - if (rc == -1) - rc = -errno; + rc = ipa_msg_recv_buffered(fd, &msg, pending_msg); + fprintf(stderr, - "ipa_msg_recv: %d, msg %s NULL\n", - rc, msg ? "!=" : "=="); - if (rc == -EAGAIN) + "ipa_msg_recv_buffered: %d, msg %s NULL, " + "pending_msg %s NULL\n", + rc, msg ? "!=" : "==", + !pending_msg ? "??" : *pending_msg ? "!=" : "=="); + if (pending_msg && !!msg == !!*pending_msg) + printf( "got msg %s NULL, pending_msg %s NULL, " + "returned: %s\n", + msg ? "!=" : "==", + *pending_msg ? "!=" : "==", + rc == 0 ? "EOF" : + rc > 0 ? "OK" : + strerror(-rc)); + else if (!pending_msg && rc == -EAGAIN) printf( "got msg %s NULL, " "returned: %s\n", msg ? "!=" : "==", @@ -115,7 +124,8 @@ static int receive_messages(int fd) if (rc == -EAGAIN) break; if (rc < 0) { - printf("ipa_msg_recv failed with: %s\n", strerror(-rc)); + printf("ipa_msg_recv_buffered failed with: %s\n", + strerror(-rc)); return rc; } printf("got IPA message, size=%d, proto=%d, text=\"%s\"\n", @@ -142,13 +152,15 @@ static int slurp_data(int fd) { return count; }; -static void test_complete_recv(void) +static void test_complete_recv(int do_not_assemble) { int sv[2]; struct msgb *msg_out = msgb_alloc(4096, "msg_out"); + struct msgb *pending_msg = NULL; int rc, i; - printf("Testing IPA recv with complete messages.\n"); + printf("Testing IPA recv with complete messages%s.\n", + do_not_assemble ? "" : " with assembling enabled"); if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) == -1) err(1, "socketpair"); @@ -166,7 +178,11 @@ static void test_complete_recv(void) } for (i=0; i < ARRAY_SIZE(ipa_test_messages); i++) { - rc = receive_messages(sv[0]); + rc = receive_messages(sv[0], + do_not_assemble ? NULL : &pending_msg); + if (pending_msg) + printf("Unexpected partial message: size=%d\n", + pending_msg->len); if (rc == 0) break; @@ -181,16 +197,19 @@ static void test_complete_recv(void) close(sv[0]); msgb_free(msg_out); + msgb_free(pending_msg); } -static void test_partial_recv(void) +static void test_partial_recv(int do_not_assemble) { int sv[2]; struct msgb *msg_out = msgb_alloc(4096, "msg_out"); + struct msgb *pending_msg = NULL; int rc, i; - printf("Testing IPA recv with partitioned messages.\n"); + printf("Testing IPA recv with partitioned messages%s.\n", + do_not_assemble ? "" : " with assembling enabled"); if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) == -1) err(1, "socketpair"); @@ -211,7 +230,8 @@ static void test_partial_recv(void) if (msg_out->len == 0) shutdown(sv[1], SHUT_WR); - rc = receive_messages(sv[0]); + rc = receive_messages(sv[0], + do_not_assemble ? NULL : &pending_msg); if (rc == 0) break; @@ -226,6 +246,7 @@ static void test_partial_recv(void) close(sv[0]); msgb_free(msg_out); + msgb_free(pending_msg); } static struct log_info info = {}; @@ -239,8 +260,10 @@ int main(int argc, char **argv) printf("Testing the IPA layer.\n"); /* run the tests */ - test_complete_recv(); - test_partial_recv(); + test_complete_recv(1); + test_partial_recv(1); + test_complete_recv(0); + test_partial_recv(0); printf("No crashes.\n"); return 0; diff --git a/tests/ipa_recv/ipa_recv_test.ok b/tests/ipa_recv/ipa_recv_test.ok index 4144d47..bdbfb7d 100644 --- a/tests/ipa_recv/ipa_recv_test.ok +++ b/tests/ipa_recv/ipa_recv_test.ok @@ -5,8 +5,31 @@ got IPA message, size=86, proto=200, text="A longer test message. ABCDEFGHIJKLMN got IPA message, size=16, proto=200, text="Hello again IPA" got IPA message, size=1, proto=200, text="" got IPA message, size=14, proto=200, text="Next is empty" -done: unread 14, unsent 0 +got msg == NULL, returned: Resource temporarily unavailable +got IPA message, size=4, proto=200, text="Bye" +got IPA message, size=4, proto=200, text="Bye" +done: unread 0, unsent 0 Testing IPA recv with partitioned messages. -ipa_msg_recv failed with: Input/output error +ipa_msg_recv_buffered failed with: Input/output error done: unread 0, unsent 154 +Testing IPA recv with complete messages with assembling enabled. +got IPA message, size=10, proto=200, text="Hello IPA" +got IPA message, size=86, proto=200, text="A longer test message. ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz" +got IPA message, size=16, proto=200, text="Hello again IPA" +got IPA message, size=1, proto=200, text="" +got IPA message, size=14, proto=200, text="Next is empty" +got msg == NULL, pending_msg == NULL, returned: Resource temporarily unavailable +got IPA message, size=4, proto=200, text="Bye" +got IPA message, size=4, proto=200, text="Bye" +done: unread 0, unsent 0 +Testing IPA recv with partitioned messages with assembling enabled. +got IPA message, size=10, proto=200, text="Hello IPA" +got IPA message, size=86, proto=200, text="A longer test message. ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz" +got IPA message, size=16, proto=200, text="Hello again IPA" +got IPA message, size=1, proto=200, text="" +got IPA message, size=14, proto=200, text="Next is empty" +got msg == NULL, pending_msg == NULL, returned: Resource temporarily unavailable +got IPA message, size=4, proto=200, text="Bye" +got IPA message, size=4, proto=200, text="Bye" +done: unread 0, unsent 0 No crashes. -- 1.7.9.5