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![Stefan Hajnoczi](/assets/img/avatar_default.png)
Slirp uses rfds/wfds/xfds more extensively than other QEMU components. The rarely-used out-of-band TCP data feature is used. That means we need the full table of select(2) to g_poll(3) events: rfds -> G_IO_IN | G_IO_HUP | G_IO_ERR wfds -> G_IO_OUT | G_IO_ERR xfds -> G_IO_PRI I came up with this table by looking at Linux fs/select.c which maps select(2) to poll(2) internally. Another detail to watch out for are the global variables that reference rfds/wfds/xfds during slirp_select_poll(). sofcantrcvmore() and sofcantsendmore() use these globals to clear fd_set bits. When sofcantrcvmore() is called, the wfds bit is cleared so that the write handler will no longer be run for this iteration of the event loop. This actually seems buggy to me since TCP connections can be half-closed and we'd still want to handle data in half-duplex fashion. I think the real intention is to avoid running the read/write handler when the socket has been fully closed. This is indicated with the SS_NOFDREF state bit so we now check for it before invoking the TCP write handler. Note that UDP/ICMP code paths don't care because they are connectionless. Note that slirp/ has a lot of tabs and sometimes mixed tabs with spaces. I followed the style of the surrounding code. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Message-id: 1361356113-11049-6-git-send-email-stefanha@redhat.com Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
98 lines
3.5 KiB
C
98 lines
3.5 KiB
C
/*
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* Copyright (c) 1995 Danny Gasparovski.
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*
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* Please read the file COPYRIGHT for the
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* terms and conditions of the copyright.
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*/
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#ifndef _SLIRP_SOCKET_H_
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#define _SLIRP_SOCKET_H_
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#define SO_EXPIRE 240000
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#define SO_EXPIREFAST 10000
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/*
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* Our socket structure
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*/
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struct socket {
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struct socket *so_next,*so_prev; /* For a linked list of sockets */
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int s; /* The actual socket */
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int pollfds_idx; /* GPollFD GArray index */
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Slirp *slirp; /* managing slirp instance */
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/* XXX union these with not-yet-used sbuf params */
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struct mbuf *so_m; /* Pointer to the original SYN packet,
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* for non-blocking connect()'s, and
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* PING reply's */
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struct tcpiphdr *so_ti; /* Pointer to the original ti within
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* so_mconn, for non-blocking connections */
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int so_urgc;
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struct in_addr so_faddr; /* foreign host table entry */
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struct in_addr so_laddr; /* local host table entry */
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uint16_t so_fport; /* foreign port */
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uint16_t so_lport; /* local port */
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uint8_t so_iptos; /* Type of service */
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uint8_t so_emu; /* Is the socket emulated? */
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u_char so_type; /* Type of socket, UDP or TCP */
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int so_state; /* internal state flags SS_*, below */
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struct tcpcb *so_tcpcb; /* pointer to TCP protocol control block */
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u_int so_expire; /* When the socket will expire */
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int so_queued; /* Number of packets queued from this socket */
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int so_nqueued; /* Number of packets queued in a row
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* Used to determine when to "downgrade" a session
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* from fastq to batchq */
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struct sbuf so_rcv; /* Receive buffer */
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struct sbuf so_snd; /* Send buffer */
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void * extra; /* Extra pointer */
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};
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/*
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* Socket state bits. (peer means the host on the Internet,
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* local host means the host on the other end of the modem)
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*/
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#define SS_NOFDREF 0x001 /* No fd reference */
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#define SS_ISFCONNECTING 0x002 /* Socket is connecting to peer (non-blocking connect()'s) */
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#define SS_ISFCONNECTED 0x004 /* Socket is connected to peer */
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#define SS_FCANTRCVMORE 0x008 /* Socket can't receive more from peer (for half-closes) */
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#define SS_FCANTSENDMORE 0x010 /* Socket can't send more to peer (for half-closes) */
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#define SS_FWDRAIN 0x040 /* We received a FIN, drain data and set SS_FCANTSENDMORE */
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#define SS_CTL 0x080
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#define SS_FACCEPTCONN 0x100 /* Socket is accepting connections from a host on the internet */
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#define SS_FACCEPTONCE 0x200 /* If set, the SS_FACCEPTCONN socket will die after one accept */
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#define SS_PERSISTENT_MASK 0xf000 /* Unremovable state bits */
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#define SS_HOSTFWD 0x1000 /* Socket describes host->guest forwarding */
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#define SS_INCOMING 0x2000 /* Connection was initiated by a host on the internet */
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struct socket * solookup(struct socket *, struct in_addr, u_int, struct in_addr, u_int);
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struct socket * socreate(Slirp *);
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void sofree(struct socket *);
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int soread(struct socket *);
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void sorecvoob(struct socket *);
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int sosendoob(struct socket *);
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int sowrite(struct socket *);
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void sorecvfrom(struct socket *);
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int sosendto(struct socket *, struct mbuf *);
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struct socket * tcp_listen(Slirp *, uint32_t, u_int, uint32_t, u_int,
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int);
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void soisfconnecting(register struct socket *);
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void soisfconnected(register struct socket *);
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void sofwdrain(struct socket *);
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struct iovec; /* For win32 */
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size_t sopreprbuf(struct socket *so, struct iovec *iov, int *np);
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int soreadbuf(struct socket *so, const char *buf, int size);
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#endif /* _SOCKET_H_ */
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