[openssl-dev] [openssl.org #3888] BUG: BIO_CTRL_DGRAM_SET_DONT_FRAG does nothing on IPv4/Linux

[Per Allansson via RT]

Is present in at least OpenSSL 1.0.2 / master.

The code in bss_dgram.c checks if  IP_MTUDISCOVER is defined, where it should test for IP_MTU_DISCOVER:

diff --git a/crypto/bio/bss_dgram.c b/crypto/bio/bss_dgram.c
index 5eade50..7cd57bf 100644
--- a/crypto/bio/bss_dgram.c
+++ b/crypto/bio/bss_dgram.c
@@ -882,7 +882,7 @@ static long dgram_ctrl(BIO *b, int cmd, long num, void *ptr)
                 perror("setsockopt");
                 ret = -1;
             }
-# elif defined(OPENSSL_SYS_LINUX) && defined(IP_MTUDISCOVER)
+# elif defined(OPENSSL_SYS_LINUX) && defined(IP_MTU_DISCOVER)
             if ((sockopt_val = num ? IP_PMTUDISC_PROBE : IP_PMTUDISC_DONT),
                 (ret = setsockopt(b->num, IPPROTO_IP, IP_MTU_DISCOVER,
                                   &sockopt_val, sizeof(sockopt_val))) < 0) {