diff options
| -rw-r--r-- | doc/platform-requirements/recv-zero.c | 60 |
1 files changed, 52 insertions, 8 deletions
diff --git a/doc/platform-requirements/recv-zero.c b/doc/platform-requirements/recv-zero.c index f161e5c..2a2a561 100644 --- a/doc/platform-requirements/recv-zero.c +++ b/doc/platform-requirements/recv-zero.c @@ -23,11 +23,27 @@ #define DSTPORT 13257U +enum discard_method { + DISCARD_NULL_BUF, + DISCARD_ZERO_IOV, + DISCARD_NULL_IOV, + NUM_METHODS, +}; + /* 127.0.0.1:DSTPORT */ static const struct sockaddr_in lo_dst = SOCKADDR_INIT(INADDR_LOOPBACK, DSTPORT); -static void test_discard(void) +static void test_discard(enum discard_method method) { + struct iovec zero_iov = { .iov_base = NULL, .iov_len = 0, }; + struct msghdr mh_zero = { + .msg_iov = &zero_iov, + .msg_iovlen = 1, + }; + struct msghdr mh_null = { + .msg_iov = NULL, + .msg_iovlen = 0, + }; long token1, token2; int recv_s, send_s; ssize_t rc; @@ -46,11 +62,36 @@ static void test_discard(void) send_token(send_s, token1); send_token(send_s, token2); - /* cppcheck-suppress nullPointer */ - rc = recv(recv_s, NULL, 0, MSG_DONTWAIT); - if (rc < 0) - die("discarding recv(): %s\n", strerror(errno)); - + switch (method) { + case DISCARD_NULL_BUF: + /* cppcheck-suppress nullPointer */ + rc = recv(recv_s, NULL, 0, MSG_DONTWAIT); + if (rc < 0) + die("discarding recv(): %s\n", strerror(errno)); + break; + + case DISCARD_ZERO_IOV: + rc = recvmsg(recv_s, &mh_zero, MSG_DONTWAIT); + if (rc < 0) + die("recvmsg() with zero-length buffer: %s\n", + strerror(errno)); + if (!((unsigned)mh_zero.msg_flags & MSG_TRUNC)) + die("Missing MSG_TRUNC flag\n"); + break; + + case DISCARD_NULL_IOV: + rc = recvmsg(recv_s, &mh_null, MSG_DONTWAIT); + if (rc < 0) + die("recvmsg() with zero-length iov: %s\n", + strerror(errno)); + if (!((unsigned)mh_null.msg_flags & MSG_TRUNC)) + die("Missing MSG_TRUNC flag\n"); + break; + + default: + die("Bad method\n"); + } + recv_token(recv_s, token2); /* cppcheck-suppress nullPointer */ @@ -63,12 +104,15 @@ static void test_discard(void) int main(int argc, char *argv[]) { + enum discard_method method; + (void)argc; (void)argv; - test_discard(); + for (method = 0; method < NUM_METHODS; method++) + test_discard(method); - printf("Discarding datagrams with a 0-length recv() seems to work\n"); + printf("Discarding datagrams with 0-length receives seems to work\n"); exit(0); } |