diff options
Diffstat (limited to 'man7/udp.7')
| -rw-r--r-- | man7/udp.7 | 28 |
1 files changed, 14 insertions, 14 deletions
@@ -4,7 +4,7 @@ .\" .\" $Id: udp.7,v 1.7 2000/01/22 01:55:05 freitag Exp $ .\" -.TH udp 7 2023-07-15 "Linux man-pages 6.05.01" +.TH udp 7 2023-10-31 "Linux man-pages 6.7" .SH NAME udp \- User Datagram Protocol for IPv4 .SH SYNOPSIS @@ -12,7 +12,7 @@ udp \- User Datagram Protocol for IPv4 .B #include <sys/socket.h> .B #include <netinet/in.h> .B #include <netinet/udp.h> -.PP +.P .IB udp_socket " = socket(AF_INET, SOCK_DGRAM, 0);" .fi .SH DESCRIPTION @@ -21,7 +21,7 @@ described in RFC\ 768. It implements a connectionless, unreliable datagram packet service. Packets may be reordered or duplicated before they arrive. UDP generates and checks checksums to catch transmission errors. -.PP +.P When a UDP socket is created, its local and remote addresses are unspecified. Datagrams can be sent immediately using @@ -50,7 +50,7 @@ a free local port out of the range defined by .I /proc/sys/net/ipv4/ip_local_port_range and bind the socket to .BR INADDR_ANY . -.PP +.P All receive operations return only one packet. When the packet is smaller than the passed buffer, only that much data is returned; when it is bigger, the packet is truncated and the @@ -58,7 +58,7 @@ data is returned; when it is bigger, the packet is truncated and the flag is set. .B MSG_WAITALL is not supported. -.PP +.P IP options may be sent or received using the socket options described in .BR ip (7). They are processed by the kernel only when the appropriate @@ -67,12 +67,12 @@ parameter is enabled (but still passed to the user even when it is turned off). See .BR ip (7). -.PP +.P When the .B MSG_DONTROUTE flag is set on sending, the destination address must refer to a local interface address and the packet is sent only to that interface. -.PP +.P By default, Linux UDP does path MTU (Maximum Transmission Unit) discovery. This means the kernel will keep track of the MTU to a specific target IP address and return @@ -106,7 +106,7 @@ This behavior differs from many other BSD socket implementations which don't pass any errors unless the socket is connected. Linux's behavior is mandated by .BR RFC\ 1122 . -.PP +.P For compatibility with legacy code, in Linux 2.0 and 2.2 it was possible to set the .B SO_BSDCOMPAT @@ -120,7 +120,7 @@ Locally generated errors are always passed. Support for this socket option was removed in later kernels; see .BR socket (7) for further information. -.PP +.P When the .B IP_RECVERR option is enabled, all errors are stored in the socket error queue, @@ -181,7 +181,7 @@ Unless otherwise noted, .I optval is a pointer to an .IR int . -.PP +.P Following is a list of UDP-specific socket options. For details of some other socket options that are also applicable for UDP sockets, see @@ -246,7 +246,7 @@ This option should not be used in code intended to be portable. These ioctls can be accessed using .BR ioctl (2). The correct syntax is: -.PP +.P .RS .nf .BI int " value"; @@ -275,7 +275,7 @@ to distinguish these cases. .BR TIOCOUTQ " (" SIOCOUTQ ) Returns the number of data bytes in the local send queue. Supported only with Linux 2.4 and above. -.PP +.P In addition, all ioctls documented in .BR ip (7) and @@ -301,10 +301,10 @@ is a new feature in Linux 2.2. .BR raw (7), .BR socket (7), .BR udplite (7) -.PP +.P The kernel source file .IR Documentation/networking/ip\-sysctl.txt . -.PP +.P RFC\ 768 for the User Datagram Protocol. .br RFC\ 1122 for the host requirements. |