Comment by _wmd

There's potential for a little rearchitecting to help, at least in the case of UDP:

    NAME
           sendmmsg - send multiple messages on a socket

    SYNOPSIS
           #define _GNU_SOURCE          /* See feature_test_macros(7) */
           #include <sys/socket.h>

           int sendmmsg(int sockfd, struct mmsghdr *msgvec, unsigned int vlen,
                        unsigned int flags);