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Source file src/net/iprawsock_posix.go

Documentation: net

     1  // Copyright 2010 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris windows
     6  
     7  package net
     8  
     9  import (
    10  	"context"
    11  	"syscall"
    12  )
    13  
    14  func sockaddrToIP(sa syscall.Sockaddr) Addr {
    15  	switch sa := sa.(type) {
    16  	case *syscall.SockaddrInet4:
    17  		return &IPAddr{IP: sa.Addr[0:]}
    18  	case *syscall.SockaddrInet6:
    19  		return &IPAddr{IP: sa.Addr[0:], Zone: zoneCache.name(int(sa.ZoneId))}
    20  	}
    21  	return nil
    22  }
    23  
    24  func (a *IPAddr) family() int {
    25  	if a == nil || len(a.IP) <= IPv4len {
    26  		return syscall.AF_INET
    27  	}
    28  	if a.IP.To4() != nil {
    29  		return syscall.AF_INET
    30  	}
    31  	return syscall.AF_INET6
    32  }
    33  
    34  func (a *IPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
    35  	if a == nil {
    36  		return nil, nil
    37  	}
    38  	return ipToSockaddr(family, a.IP, 0, a.Zone)
    39  }
    40  
    41  func (a *IPAddr) toLocal(net string) sockaddr {
    42  	return &IPAddr{loopbackIP(net), a.Zone}
    43  }
    44  
    45  func (c *IPConn) readFrom(b []byte) (int, *IPAddr, error) {
    46  	// TODO(cw,rsc): consider using readv if we know the family
    47  	// type to avoid the header trim/copy
    48  	var addr *IPAddr
    49  	n, sa, err := c.fd.readFrom(b)
    50  	switch sa := sa.(type) {
    51  	case *syscall.SockaddrInet4:
    52  		addr = &IPAddr{IP: sa.Addr[0:]}
    53  		n = stripIPv4Header(n, b)
    54  	case *syscall.SockaddrInet6:
    55  		addr = &IPAddr{IP: sa.Addr[0:], Zone: zoneCache.name(int(sa.ZoneId))}
    56  	}
    57  	return n, addr, err
    58  }
    59  
    60  func stripIPv4Header(n int, b []byte) int {
    61  	if len(b) < 20 {
    62  		return n
    63  	}
    64  	l := int(b[0]&0x0f) << 2
    65  	if 20 > l || l > len(b) {
    66  		return n
    67  	}
    68  	if b[0]>>4 != 4 {
    69  		return n
    70  	}
    71  	copy(b, b[l:])
    72  	return n - l
    73  }
    74  
    75  func (c *IPConn) readMsg(b, oob []byte) (n, oobn, flags int, addr *IPAddr, err error) {
    76  	var sa syscall.Sockaddr
    77  	n, oobn, flags, sa, err = c.fd.readMsg(b, oob)
    78  	switch sa := sa.(type) {
    79  	case *syscall.SockaddrInet4:
    80  		addr = &IPAddr{IP: sa.Addr[0:]}
    81  	case *syscall.SockaddrInet6:
    82  		addr = &IPAddr{IP: sa.Addr[0:], Zone: zoneCache.name(int(sa.ZoneId))}
    83  	}
    84  	return
    85  }
    86  
    87  func (c *IPConn) writeTo(b []byte, addr *IPAddr) (int, error) {
    88  	if c.fd.isConnected {
    89  		return 0, ErrWriteToConnected
    90  	}
    91  	if addr == nil {
    92  		return 0, errMissingAddress
    93  	}
    94  	sa, err := addr.sockaddr(c.fd.family)
    95  	if err != nil {
    96  		return 0, err
    97  	}
    98  	return c.fd.writeTo(b, sa)
    99  }
   100  
   101  func (c *IPConn) writeMsg(b, oob []byte, addr *IPAddr) (n, oobn int, err error) {
   102  	if c.fd.isConnected {
   103  		return 0, 0, ErrWriteToConnected
   104  	}
   105  	if addr == nil {
   106  		return 0, 0, errMissingAddress
   107  	}
   108  	sa, err := addr.sockaddr(c.fd.family)
   109  	if err != nil {
   110  		return 0, 0, err
   111  	}
   112  	return c.fd.writeMsg(b, oob, sa)
   113  }
   114  
   115  func dialIP(ctx context.Context, netProto string, laddr, raddr *IPAddr) (*IPConn, error) {
   116  	network, proto, err := parseNetwork(ctx, netProto, true)
   117  	if err != nil {
   118  		return nil, err
   119  	}
   120  	switch network {
   121  	case "ip", "ip4", "ip6":
   122  	default:
   123  		return nil, UnknownNetworkError(netProto)
   124  	}
   125  	if raddr == nil {
   126  		return nil, errMissingAddress
   127  	}
   128  	fd, err := internetSocket(ctx, network, laddr, raddr, syscall.SOCK_RAW, proto, "dial")
   129  	if err != nil {
   130  		return nil, err
   131  	}
   132  	return newIPConn(fd), nil
   133  }
   134  
   135  func listenIP(ctx context.Context, netProto string, laddr *IPAddr) (*IPConn, error) {
   136  	network, proto, err := parseNetwork(ctx, netProto, true)
   137  	if err != nil {
   138  		return nil, err
   139  	}
   140  	switch network {
   141  	case "ip", "ip4", "ip6":
   142  	default:
   143  		return nil, UnknownNetworkError(netProto)
   144  	}
   145  	fd, err := internetSocket(ctx, network, laddr, nil, syscall.SOCK_RAW, proto, "listen")
   146  	if err != nil {
   147  		return nil, err
   148  	}
   149  	return newIPConn(fd), nil
   150  }
   151  

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