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diff --git a/man7/raw.7 b/man7/raw.7 deleted file mode 100644 index 65cdbe0..0000000 --- a/man7/raw.7 +++ /dev/null @@ -1,281 +0,0 @@ -'\" t -.\" SPDX-License-Identifier: Linux-man-pages-1-para -.\" -.\" This man page is Copyright (C) 1999 Andi Kleen <ak@muc.de>. -.\" -.\" $Id: raw.7,v 1.6 1999/06/05 10:32:08 freitag Exp $ -.\" -.TH raw 7 2023-10-31 "Linux man-pages 6.7" -.SH NAME -raw \- Linux IPv4 raw sockets -.SH SYNOPSIS -.nf -.B #include <sys/socket.h> -.B #include <netinet/in.h> -.BI "raw_socket = socket(AF_INET, SOCK_RAW, int " protocol ); -.fi -.SH DESCRIPTION -Raw sockets allow new IPv4 protocols to be implemented in user space. -A raw socket receives or sends the raw datagram not -including link level headers. -.P -The IPv4 layer generates an IP header when sending a packet unless the -.B IP_HDRINCL -socket option is enabled on the socket. -When it is enabled, the packet must contain an IP header. -For receiving, the IP header is always included in the packet. -.P -In order to create a raw socket, a process must have the -.B CAP_NET_RAW -capability in the user namespace that governs its network namespace. -.P -All packets or errors matching the -.I protocol -number specified -for the raw socket are passed to this socket. -For a list of the allowed protocols, -see the IANA list of assigned protocol numbers at -.UR http://www.iana.org/assignments/protocol\-numbers/ -.UE -and -.BR getprotobyname (3). -.P -A protocol of -.B IPPROTO_RAW -implies enabled -.B IP_HDRINCL -and is able to send any IP protocol that is specified in the passed -header. -Receiving of all IP protocols via -.B IPPROTO_RAW -is not possible using raw sockets. -.RS -.TS -tab(:) allbox; -c s -l l. -IP Header fields modified on sending by \fBIP_HDRINCL\fP -IP Checksum:Always filled in -Source Address:Filled in when zero -Packet ID:Filled in when zero -Total Length:Always filled in -.TE -.RE -.P -If -.B IP_HDRINCL -is specified and the IP header has a nonzero destination address, then -the destination address of the socket is used to route the packet. -When -.B MSG_DONTROUTE -is specified, the destination address should refer to a local interface, -otherwise a routing table lookup is done anyway but gatewayed routes -are ignored. -.P -If -.B IP_HDRINCL -isn't set, then IP header options can be set on raw sockets with -.BR setsockopt (2); -see -.BR ip (7) -for more information. -.P -Starting with Linux 2.2, all IP header fields and options can be set using -IP socket options. -This means raw sockets are usually needed only for new -protocols or protocols with no user interface (like ICMP). -.P -When a packet is received, it is passed to any raw sockets which have -been bound to its protocol before it is passed to other protocol handlers -(e.g., kernel protocol modules). -.SS Address format -For sending and receiving datagrams -.RB ( sendto (2), -.BR recvfrom (2), -and similar), -raw sockets use the standard -.I sockaddr_in -address structure defined in -.BR ip (7). -The -.I sin_port -field could be used to specify the IP protocol number, -but it is ignored for sending in Linux 2.2 and later, and should be always -set to 0 (see BUGS). -For incoming packets, -.I sin_port -.\" commit f59fc7f30b710d45aadf715460b3e60dbe9d3418 -is set to zero. -.SS Socket options -Raw socket options can be set with -.BR setsockopt (2) -and read with -.BR getsockopt (2) -by passing the -.B IPPROTO_RAW -.\" Or SOL_RAW on Linux -family flag. -.TP -.B ICMP_FILTER -Enable a special filter for raw sockets bound to the -.B IPPROTO_ICMP -protocol. -The value has a bit set for each ICMP message type which -should be filtered out. -The default is to filter no ICMP messages. -.P -In addition, all -.BR ip (7) -.B IPPROTO_IP -socket options valid for datagram sockets are supported. -.SS Error handling -Errors originating from the network are passed to the user only when the -socket is connected or the -.B IP_RECVERR -flag is enabled. -For connected sockets, only -.B EMSGSIZE -and -.B EPROTO -are passed for compatibility. -With -.BR IP_RECVERR , -all network errors are saved in the error queue. -.SH ERRORS -.TP -.B EACCES -User tried to send to a broadcast address without having the -broadcast flag set on the socket. -.TP -.B EFAULT -An invalid memory address was supplied. -.TP -.B EINVAL -Invalid argument. -.TP -.B EMSGSIZE -Packet too big. -Either Path MTU Discovery is enabled (the -.B IP_MTU_DISCOVER -socket flag) or the packet size exceeds the maximum allowed IPv4 -packet size of 64\ kB. -.TP -.B EOPNOTSUPP -Invalid flag has been passed to a socket call (like -.BR MSG_OOB ). -.TP -.B EPERM -The user doesn't have permission to open raw sockets. -Only processes with an effective user ID of 0 or the -.B CAP_NET_RAW -attribute may do that. -.TP -.B EPROTO -An ICMP error has arrived reporting a parameter problem. -.SH VERSIONS -.B IP_RECVERR -and -.B ICMP_FILTER -are new in Linux 2.2. -They are Linux extensions and should not be used in portable programs. -.P -Linux 2.0 enabled some bug-to-bug compatibility with BSD in the -raw socket code when the -.B SO_BSDCOMPAT -socket option was set; since Linux 2.2, -this option no longer has that effect. -.SH NOTES -By default, raw sockets do path MTU (Maximum Transmission Unit) discovery. -This means the kernel -will keep track of the MTU to a specific target IP address and return -.B EMSGSIZE -when a raw packet write exceeds it. -When this happens, the application should decrease the packet size. -Path MTU discovery can be also turned off using the -.B IP_MTU_DISCOVER -socket option or the -.I /proc/sys/net/ipv4/ip_no_pmtu_disc -file, see -.BR ip (7) -for details. -When turned off, raw sockets will fragment outgoing packets -that exceed the interface MTU. -However, disabling it is not recommended -for performance and reliability reasons. -.P -A raw socket can be bound to a specific local address using the -.BR bind (2) -call. -If it isn't bound, all packets with the specified IP protocol are received. -In addition, a raw socket can be bound to a specific network device using -.BR SO_BINDTODEVICE ; -see -.BR socket (7). -.P -An -.B IPPROTO_RAW -socket is send only. -If you really want to receive all IP packets, use a -.BR packet (7) -socket with the -.B ETH_P_IP -protocol. -Note that packet sockets don't reassemble IP fragments, -unlike raw sockets. -.P -If you want to receive all ICMP packets for a datagram socket, -it is often better to use -.B IP_RECVERR -on that particular socket; see -.BR ip (7). -.P -Raw sockets may tap all IP protocols in Linux, even -protocols like ICMP or TCP which have a protocol module in the kernel. -In this case, the packets are passed to both the kernel module and the raw -socket(s). -This should not be relied upon in portable programs, many other BSD -socket implementation have limitations here. -.P -Linux never changes headers passed from the user (except for filling -in some zeroed fields as described for -.BR IP_HDRINCL ). -This differs from many other implementations of raw sockets. -.P -Raw sockets are generally rather unportable and should be avoided in -programs intended to be portable. -.P -Sending on raw sockets should take the IP protocol from -.IR sin_port ; -this ability was lost in Linux 2.2. -The workaround is to use -.BR IP_HDRINCL . -.SH BUGS -Transparent proxy extensions are not described. -.P -When the -.B IP_HDRINCL -option is set, datagrams will not be fragmented and are limited to -the interface MTU. -.P -Setting the IP protocol for sending in -.I sin_port -got lost in Linux 2.2. -The protocol that the socket was bound to or that -was specified in the initial -.BR socket (2) -call is always used. -.\" .SH AUTHORS -.\" This man page was written by Andi Kleen. -.SH SEE ALSO -.BR recvmsg (2), -.BR sendmsg (2), -.BR capabilities (7), -.BR ip (7), -.BR socket (7) -.P -.B RFC\ 1191 -for path MTU discovery. -.B RFC\ 791 -and the -.I <linux/ip.h> -header file for the IP protocol. |