unix/dgram: add a specific send method - uipc_sosend_dgram()
This is first step towards splitting classic BSD socket implementation into separate classes. The first to be split is PF_UNIX/SOCK_DGRAM as it has most differencies to SOCK_STREAM sockets and to PF_INET sockets. Historically a protocol shall provide two methods for sendmsg(2): pru_sosend and pru_send. The former is a generic send method, e.g. sosend_generic() which would internally call the latter, uipc_send() in our case. There is one important exception, though, the sendfile(2) code will call pru_send directly. But sendfile doesn't work on SOCK_DGRAM, so we can do the trick. We will create socket class specific uipc_sosend_dgram() which will carry only important bits from sosend_generic() and uipc_send(). Reviewed by: markj Differential revision: https://reviews.freebsd.org/D35293
This commit is contained in:
Gleb Smirnoff
parent
bc6d0d72f4
commit
3464958246
@ -996,8 +996,7 @@ uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
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unp = sotounpcb(so);
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KASSERT(unp != NULL, ("%s: unp == NULL", __func__));
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KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_DGRAM ||
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so->so_type == SOCK_SEQPACKET,
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KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET,
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("%s: socktype %d", __func__, so->so_type));
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error = 0;
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@ -1173,6 +1172,146 @@ uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
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return (error);
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}
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/*
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* PF_UNIX/SOCK_DGRAM send
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*/
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static int
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uipc_sosend_dgram(struct socket *so, struct sockaddr *addr, struct uio *uio,
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struct mbuf *m, struct mbuf *c, int flags, struct thread *td)
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{
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struct unpcb *unp, *unp2;
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const struct sockaddr *from;
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struct socket *so2;
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int error;
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MPASS((uio != NULL && m == NULL) || (m != NULL && uio == NULL));
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error = 0;
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if (__predict_false(flags & MSG_OOB)) {
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error = EOPNOTSUPP;
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goto out;
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}
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if (m == NULL) {
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if (__predict_false(uio->uio_resid > unpdg_maxdgram)) {
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error = EMSGSIZE;
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goto out;
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}
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m = m_uiotombuf(uio, M_WAITOK, 0, max_hdr, M_PKTHDR);
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if (__predict_false(m == NULL)) {
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error = EFAULT;
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goto out;
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}
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if (c != NULL && (error = unp_internalize(&c, td)))
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goto out;
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} else {
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/* pru_sosend() with mbuf usually is a kernel thread. */
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M_ASSERTPKTHDR(m);
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if (__predict_false(c != NULL))
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panic("%s: control from a kernel thread", __func__);
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if (__predict_false(m->m_pkthdr.len > unpdg_maxdgram)) {
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error = EMSGSIZE;
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goto out;
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}
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/* Condition the foreign mbuf to our standards. */
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m_clrprotoflags(m);
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m_tag_delete_chain(m, NULL);
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m->m_pkthdr.rcvif = NULL;
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m->m_pkthdr.flowid = 0;
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m->m_pkthdr.csum_flags = 0;
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m->m_pkthdr.fibnum = 0;
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m->m_pkthdr.rsstype = 0;
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}
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unp = sotounpcb(so);
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MPASS(unp);
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/*
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* XXXGL: would be cool to fully remove so_snd out of the equation
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* and avoid this lock, which is not only extraneous, but also being
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* released, thus still leaving possibility for a race. We can easily
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* handle SBS_CANTSENDMORE/SS_ISCONNECTED complement in unpcb, but it
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* is more difficult to invent something to handle so_error.
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*/
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error = SOCK_IO_SEND_LOCK(so, SBLOCKWAIT(flags));
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if (error)
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goto out2;
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SOCKBUF_LOCK(&so->so_snd);
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if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
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SOCK_SENDBUF_UNLOCK(so);
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error = EPIPE;
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goto out3;
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}
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if (so->so_error != 0) {
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error = so->so_error;
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so->so_error = 0;
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SOCKBUF_UNLOCK(&so->so_snd);
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goto out3;
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}
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if (((so->so_state & SS_ISCONNECTED) == 0) && addr == NULL) {
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SOCKBUF_UNLOCK(&so->so_snd);
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error = EDESTADDRREQ;
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goto out3;
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}
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SOCKBUF_UNLOCK(&so->so_snd);
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if (addr != NULL && (error = unp_connect(so, addr, td)))
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goto out3;
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UNP_PCB_LOCK(unp);
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/*
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* Because connect() and send() are non-atomic in a sendto() with a
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* target address, it's possible that the socket will have disconnected
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* before the send() can run. In that case return the slightly
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* counter-intuitive but otherwise correct error that the socket is not
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* connected.
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*/
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unp2 = unp_pcb_lock_peer(unp);
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if (unp2 == NULL) {
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UNP_PCB_UNLOCK(unp);
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error = ENOTCONN;
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goto out3;
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}
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if (unp2->unp_flags & UNP_WANTCRED_MASK)
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c = unp_addsockcred(td, c, unp2->unp_flags);
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if (unp->unp_addr != NULL)
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from = (struct sockaddr *)unp->unp_addr;
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else
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from = &sun_noname;
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so2 = unp2->unp_socket;
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SOCKBUF_LOCK(&so2->so_rcv);
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if (sbappendaddr_locked(&so2->so_rcv, from, m, c)) {
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sorwakeup_locked(so2);
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m = c = NULL;
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} else {
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soroverflow_locked(so2);
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error = (so->so_state & SS_NBIO) ? EAGAIN : ENOBUFS;
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}
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if (addr != NULL)
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unp_disconnect(unp, unp2);
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else
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unp_pcb_unlock_pair(unp, unp2);
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td->td_ru.ru_msgsnd++;
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out3:
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SOCK_IO_SEND_UNLOCK(so);
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out2:
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if (c)
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unp_scan(c, unp_freerights);
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out:
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if (c)
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m_freem(c);
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if (m)
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m_freem(m);
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return (error);
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}
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static bool
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uipc_ready_scan(struct socket *so, struct mbuf *m, int count, int *errorp)
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{
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@ -1314,7 +1453,7 @@ static struct pr_usrreqs uipc_usrreqs_dgram = {
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.pru_detach = uipc_detach,
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.pru_disconnect = uipc_disconnect,
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.pru_peeraddr = uipc_peeraddr,
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.pru_send = uipc_send,
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.pru_sosend = uipc_sosend_dgram,
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.pru_sense = uipc_sense,
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.pru_shutdown = uipc_shutdown,
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.pru_sockaddr = uipc_sockaddr,
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