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socket/netconn recv: FIN should only be reported once

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FIN should only be reported once (as '0' for sockets, as 'ERR_CLSD' for
netconns). Before this change, ERR_CLSD was returned forever...

This is the 2nd try. First try (commit ebcae98ae6)
was buggy in that it could drop the FIN if it was read together with data
(reverted in commit ebcae98ae6).

This version fixes this by adding an apiflag and a netconn flag to keep
track of this.
This commit is contained in:
goldsimon
2018-02-04 20:16:53 +01:00
parent fe828634ac
commit b1b6275110
4 changed files with 33 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
src/api/api_lib.c
View File

@@ -646,8 +646,12 @@ netconn_recv_data_tcp(struct netconn *conn, struct pbuf **new_buf, u8_t apiflags
#endif /* LWIP_TCP */
if (!sys_mbox_valid(&conn->recvmbox)) {
/* This happens when calling this function after receiving FIN */
return sys_mbox_valid(&conn->acceptmbox) ? ERR_CONN : ERR_CLSD;
/* This only happens when calling this function more than once *after* receiving FIN */
return ERR_CONN;
}
if (netconn_is_flag_set(conn, NETCONN_FIN_RX_PENDING)) {
netconn_clear_flags(conn, NETCONN_FIN_RX_PENDING);
goto handle_fin;
}
if (!(apiflags & NETCONN_NOAUTORCVD)) {
@@ -675,19 +679,27 @@ netconn_recv_data_tcp(struct netconn *conn, struct pbuf **new_buf, u8_t apiflags
/* If we are closed, we indicate that we no longer wish to use the socket */
if (buf == NULL) {
API_EVENT(conn, NETCONN_EVT_RCVMINUS, 0);
if (conn->pcb.ip == NULL) {
/* race condition: RST during recv */
err = netconn_err(conn);
if (err != ERR_OK) {
return err;
if (apiflags & NETCONN_NOFIN) {
/* received a FIN but the caller cannot handle it right now:
re-enqueue it and return "no data" */
netconn_set_flags(conn, NETCONN_FIN_RX_PENDING);
return ERR_WOULDBLOCK;
} else {
handle_fin:
API_EVENT(conn, NETCONN_EVT_RCVMINUS, 0);
if (conn->pcb.ip == NULL) {
/* race condition: RST during recv */
err = netconn_err(conn);
if (err != ERR_OK) {
return err;
}
return ERR_RST;
}
return ERR_RST;
/* RX side is closed, so deallocate the recvmbox */
netconn_close_shutdown(conn, NETCONN_SHUT_RD);
/* Don' store ERR_CLSD as conn->err since we are only half-closed */
return ERR_CLSD;
}
/* RX side is closed, so deallocate the recvmbox */
netconn_close_shutdown(conn, NETCONN_SHUT_RD);
/* Don' store ERR_CLSD as conn->err since we are only half-closed */
return ERR_CLSD;
}
return err;
}

2
src/api/sockets.c
View File

@@ -956,7 +956,7 @@ lwip_recv_tcp(struct lwip_sock *sock, void *mem, size_t len, int flags)
}
}
/* once we have some data to return, only add more if we don't need to wait */
apiflags |= NETCONN_DONTBLOCK;
apiflags |= NETCONN_DONTBLOCK | NETCONN_NOFIN;
/* @todo: do we need to support peeking more than one pbuf? */
} while ((recv_left > 0) && !(flags & MSG_PEEK));
lwip_recv_tcp_done: