Skip to content

Commit 0394e26

Browse files
davidge20davidge20
committed
Final comments
1 parent 550afcf commit 0394e26

File tree

1 file changed

+72
-53
lines changed

1 file changed

+72
-53
lines changed

‎src/safeposix/syscalls/net_calls.rs‎

Lines changed: 72 additions & 53 deletions
Original file line numberDiff line numberDiff line change
@@ -1512,91 +1512,79 @@ impl Cage {
15121512

15131513
/// ### Description
15141514
///
1515-
/// `accept_syscall` accepts a connection on a socket
1515+
/// `listen_syscall` listen for connections on a socket
15161516
///
15171517
/// ### Arguments
15181518
///
15191519
/// it accepts two parameters:
1520-
/// * `fd` - the file descriptor that refers to the listening socket
1521-
/// * `addr` - the address of the peer socket (i.e. the client that is connecting)
1522-
/// // ** Do we deal with the case in which addr may be NULL ?? ** //
1520+
/// * `sockfd` - a file descriptor that refers to a socket
1521+
/// of type SOCK_STREAM or SOCK_SEQPACKET.
1522+
/// // ** Do we deal with SOCK_SEQPACKET ?? ** //
1523+
/// * `backlog` - defines the maximum length to which the
1524+
/// queue of pending connections for sockfd may grow. If a
1525+
/// connection request arrives when the queue is full, the client may
1526+
/// receive an error with an indication of ECONNREFUSED or, if the
1527+
/// underlying protocol supports retransmission, the request may be
1528+
/// ignored so that a later reattempt at connection succeeds.
15231529
///
15241530
/// ### Returns
15251531
///
1526-
/// for a successful call, the return value will be a file descriptor for the
1527-
/// accepted socket (a nonnegative integer). On error, -errno is
1532+
/// for a successful call, zero is returned. On error, -errno is
15281533
/// returned and errno is set to indicate the error
15291534
///
15301535
/// ### Errors
15311536
///
1532-
/// * EAGAIN or EWOULDBLOCK - The socket is marked nonblocking and no
1533-
/// connections are present to be accepted.
1534-
/// POSIX.1-2001 and POSIX.1-2008
1535-
/// allow either error to be returned for this case, and do
1536-
/// not require these constants to have the same value, so a
1537-
/// portable application should check for both possibilities.
1537+
/// * EADDRINUSE - Another socket is already listening on the same port.
15381538
///
1539-
/// * EBADF - sockfd is not an open file descriptor.
1539+
/// * EADDRINUSE - (Internet domain sockets) The socket referred to by sockfd
1540+
/// had not previously been bound to an address and, upon
1541+
/// attempting to bind it to an ephemeral port, it was
1542+
/// determined that all port numbers in the ephemeral port
1543+
/// range are currently in use. See the discussion of
1544+
/// /proc/sys/net/ipv4/ip_local_port_range in ip(7).
15401545
///
1541-
/// * ECONNABORTED - A connection has been aborted.
1542-
///
1543-
/// * EFAULT - The addr argument is not in a writable part of the user
1544-
/// address space.
1545-
///
1546-
/// * EINTR - The system call was interrupted by a signal that was
1547-
/// caught before a valid connection arrived; see signal(7).
1548-
///
1549-
/// * EINVAL - Socket is not listening for connections, or addrlen is
1550-
/// invalid (e.g., is negative).
1551-
///
1552-
/// * EMFILE - The per-process limit on the number of open file
1553-
/// descriptors has been reached.
1554-
///
1555-
/// * ENFILE - The system-wide limit on the total number of open files
1556-
/// has been reached.
1557-
///
1558-
/// * ENOMEM - Not enough free memory. This often means that the memory
1559-
/// allocation is limited by the socket buffer limits, not by
1560-
/// the system memory.
1546+
/// * EBADF - The argument sockfd is not a valid file descriptor.
15611547
///
15621548
/// * ENOTSOCK - The file descriptor sockfd does not refer to a socket.
15631549
///
1564-
/// * EOPNOTSUPP - The referenced socket is not of type SOCK_STREAM.
1565-
///
1566-
/// * EPERM - Firewall rules forbid connection.
1567-
///
1568-
/// * EPROTO - Protocol error.
1569-
///
1570-
/// In addition, network errors for the new socket and as defined for
1571-
/// the protocol may be returned. Various Linux kernels can return
1572-
/// other errors such as ENOSR, ESOCKTNOSUPPORT, EPROTONOSUPPORT,
1573-
/// ETIMEDOUT. The value ERESTARTSYS may be seen during a trace.
1550+
/// * EOPNOTSUPP - The socket is not of a type that supports the listen()
1551+
/// operation.
15741552
///
15751553
/// ### Panics
15761554
///
15771555
/// * invalid or out-of-bounds file descriptor), calling unwrap() on it will cause a panic.
1578-
/// * Unknown errno value from fcntl returned, will cause panic.
1556+
/// * unknown errno value from socket bind sys call from libc in the case
1557+
/// that the socket isn't assigned an address
1558+
/// * unknown errno value from socket listen sys call from libc
15791559
///
15801560
/// for more detailed description of all the commands and return values, see
1581-
/// [accept(2)](https://linux.die.net/man/2/accept)
1561+
/// [listen(2)](https://linux.die.net/man/2/listen)
15821562
//
1583-
// ** we currently ignore backlog **
1584-
// ** What does the above comment mean ?? ** //
1563+
// TODO: We are currently ignoring backlog
15851564
pub fn listen_syscall(&self, fd: i32, _backlog: i32) -> i32 {
1565+
//If fd is out of range of [0,MAXFD], process will panic
1566+
//Otherwise, we obtain a write gaurd to the Option<FileDescriptor> object
15861567
let checkedfd = self.get_filedescriptor(fd).unwrap();
15871568
let mut unlocked_fd = checkedfd.write();
15881569
if let Some(filedesc_enum) = &mut *unlocked_fd {
15891570
match filedesc_enum {
1571+
//If the file descriptor refers to a socket
15901572
Socket(ref mut sockfdobj) => {
15911573
//get or create the socket and bind it before listening
1574+
//Gain write access to the socket handle
15921575
let sock_tmp = sockfdobj.handle.clone();
15931576
let mut sockhandle = sock_tmp.write();
15941577

1578+
//If the given socket is already listening, return with
1579+
//success
15951580
match sockhandle.state {
15961581
ConnState::LISTEN => {
1597-
return 0; //Already done!
1582+
return 0;
15981583
}
15991584

1585+
//If the given socket is connected to another socket or
1586+
//if a non blocking socket is in progress of connecting
1587+
//to another socket
16001588
ConnState::CONNECTED
16011589
| ConnState::CONNRDONLY
16021590
| ConnState::CONNWRONLY
@@ -1608,7 +1596,11 @@ impl Cage {
16081596
);
16091597
}
16101598

1599+
//If the given socket is not connected, it is ready
1600+
//to begin listening
16111601
ConnState::NOTCONNECTED => {
1602+
//If the given socket is not a TCP socket, then the
1603+
//socket can not listen for connections
16121604
if sockhandle.protocol != IPPROTO_TCP {
16131605
return syscall_error(
16141606
Errno::EOPNOTSUPP,
@@ -1617,12 +1609,15 @@ impl Cage {
16171609
);
16181610
}
16191611

1620-
// simple if it's a domain socket
1612+
//If the given socket is a Unix socket, lind handles
1613+
//the connection, return with success
16211614
if sockhandle.domain == AF_UNIX {
16221615
sockhandle.state = ConnState::LISTEN;
16231616
return 0;
16241617
}
16251618

1619+
//If the given socket is not assigned an address,
1620+
//attempt to bind the socket to an address.
16261621
if sockhandle.localaddr.is_none() {
16271622
let shd = sockhandle.domain as i32;
16281623
let ibindret = self._implicit_bind(&mut *sockhandle, shd);
@@ -1634,18 +1629,27 @@ impl Cage {
16341629
}
16351630
}
16361631

1637-
let ladr = sockhandle.localaddr.unwrap().clone(); //must have been populated by implicit bind
1632+
//The socket must have been assigned an address by implicit bind
1633+
let ladr = sockhandle.localaddr.unwrap().clone();
1634+
//Grab a tuple of the address, port, and port type
1635+
//to be inserted into the set of listening ports
16381636
let porttuple = mux_port(
16391637
ladr.addr().clone(),
16401638
ladr.port(),
16411639
sockhandle.domain,
16421640
TCPPORT,
16431641
);
16441642

1643+
//Set the socket connection state to listening
1644+
//to readily accept connections
16451645
NET_METADATA.listening_port_set.insert(porttuple.clone());
16461646
sockhandle.state = ConnState::LISTEN;
16471647

1648-
let listenret = sockhandle.innersocket.as_ref().unwrap().listen(5); //default backlog in repy for whatever reason, we replicate it
1648+
//Call listen from libc on the socket
1649+
//Set the backlog to 5:
1650+
//default backlog in repy for whatever reason, we replicate it
1651+
//** Would we ever want to change the backlog?? **/
1652+
let listenret = sockhandle.innersocket.as_ref().unwrap().listen(5);
16491653
if listenret < 0 {
16501654
let lr = match Errno::from_discriminant(interface::get_errno()) {
16511655
Ok(i) => syscall_error(
@@ -1657,30 +1661,44 @@ impl Cage {
16571661
panic!("Unknown errno value from socket listen returned!")
16581662
}
16591663
};
1664+
//Remove the tuple of the address, port, and
1665+
//port type from the set of listening ports
1666+
//as we are returning from an error
1667+
//** Why dont we use 'porttuple' as the argument for the key ?? */
16601668
NET_METADATA.listening_port_set.remove(&mux_port(
16611669
ladr.addr().clone(),
16621670
ladr.port(),
16631671
sockhandle.domain,
16641672
TCPPORT,
16651673
));
1674+
//Set the socket state to NOTCONNECTED, as
1675+
//the socket is not listening
16661676
sockhandle.state = ConnState::NOTCONNECTED;
16671677
return lr;
16681678
};
16691679

1670-
//set rawfd for select
1680+
//set rawfd for select sys call
1681+
//** Why is this being done in listen ??
1682+
// We are also doing it in connect right now **/
16711683
sockfdobj.rawfd = sockhandle.innersocket.as_ref().unwrap().raw_sys_fd;
16721684

1685+
//If listening socket is not in the table of pending
1686+
//connections, we must insert it as the key with
1687+
//an empty vector as the value
1688+
//We can now track incoming connections
16731689
if !NET_METADATA.pending_conn_table.contains_key(&porttuple) {
16741690
NET_METADATA
16751691
.pending_conn_table
16761692
.insert(porttuple.clone(), vec![]);
16771693
}
16781694

1679-
return 0;
1695+
return 0; //return on success
16801696
}
16811697
}
16821698
}
16831699

1700+
//Otherwise, the file descriptor refers to something other
1701+
//than a socket, return with error
16841702
_ => {
16851703
return syscall_error(
16861704
Errno::ENOTSOCK,
@@ -1689,6 +1707,7 @@ impl Cage {
16891707
);
16901708
}
16911709
}
1710+
//Otherwise, file descriptor is invalid, return with error
16921711
} else {
16931712
return syscall_error(Errno::EBADF, "listen", "invalid file descriptor");
16941713
}

0 commit comments

Comments
 (0)
⚡