IP.4
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- IP(4) Minix Programmer's Manual IP(4)
- NAME
- ip, eth, psip, udp, tcp - Internet Protocol server devices and
- definitions
- DESCRIPTION
- The ip*, eth*, psip*, tcp*, and udp* devices give access to the Internet
- Protocol (IP) services in Minix. There are 16 such devices for four
- different networks, and four different ways of accessing them. The eth*
- and psip* devices give direct access to the network packets at the lowest
- level. The ip*, tcp*, and udp* devices give access to IP, TCP, or UDP
- services. See set_net_default(8) for a description of the default
- network devices and environment variables. The proper TCP device to use
- for instance is found by:
- if ((tcp_device= getenv("TCP_DEVICE")) == NULL)
- tcp_device= "/dev/tcp";
- Access to the IP services is provided using filedescriptors to open IP
- devices. These open IP channels can be configured with ioctl(2) calls,
- and data can be transferred by calls to read(2), and write(2).
- Types (general)
- <sys/types.h>
- defines u8_t, u16_t, u32_t and i32_t (and U8_t, U16_t, U32_t and
- I32_t for use in prototypes).
- Types (eth)
- <net/gen/ether.h>
- defines struct ether_addr (ether_addr_t) and ether_type_t and
- Ether_type_t for use in prototypes.
- <net/gen/eth_io.h>
- defines struct nwio_ethopt (nwio_ethopt_t) and struct nwio_ethstat
- (nwio_ethstat_t)
- <net/gen/eth_hdr.h>
- defines struct eth_hdr (eth_hdr_t)
- Types (ip)
- <net/gen/in.h>
- defines ipaddr_t, ipproto_t and struct ip_hdropt (ip_hdropt_t).
- <net/gen/ip_io.h>
- defines struct nwio_ipconf (nwio_ipconf_t) and struct nwio_ipopt
- (nwio_ipopt_t)
- 1
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- IP(4) Minix Programmer's Manual IP(4)
- <net/gen/ip_hdr.h>
- defines struct ip_hdr (ip_hdr_t)
- <net/gen/route.h>
- defines struct nwio_route (nwio_route_t)
- Types (tcp)
- <net/gen/tcp.h>
- defines tcpport_t and Tcpport_t for use in prototypes.
- <net/gen/tcp_io.h>
- defines struct nwio_tcpconf (nwio_tcpconf_t), struct nwio_tcpcl
- (nwio_tcpcl_t), struct nwio_tcpatt (nwio_tcpatt_t) and struct
- nwio_tcpopt (nwio_tcpopt_t).
- <net/gen/tcp_hdr.h>
- defines struct tcp_hdr (tcp_hdr_t) and struct tcp_hdropt
- (tcp_hdropt_t).
- Types (udp)
- <net/gen/udp.h>
- defines udpport_t and Udpport_t for use in prototypes.
- <net/gen/udp_io.h>
- defines struct nwio_udpopt (nwio_udpopt_t).
- <net/gen/udp_hdr.h>
- defines struct udp_hdr (udp_hdr_t) and struct udp_io_hdr
- (udp_io_hdr_t).
- Byte Order Conversion
- All 16-bit and 32-bit quantities in IP headers must be in network byte
- order. The macros described in hton(3) can be used to convert these
- values to and from the byte order used by the host machine.
- The Internet Checksum
- The OneC_sum function (see oneC_sum(3)) is used to calculate the one's
- complement checksum needed for IP network packets.
- General Functions
- fd = open(tcpip_device, O_RDWR)
- This is how one normally obtains a filedescriptor for a new TCP/IP
- channel. tcpip_device names one of the TCP/IP devices. The channel may
- be used both to send or to receive data.
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- n = read(fd, buf, size)
- Receives one packet (low level devices) or a number of bytes (TCP
- stream). Returns the the number of bytes placed into buf, or returns -1
- with an error code placed into errno.
- n = write(fd, buf, size)
- Sends one packet (low level devices) or a number of bytes (TCP stream).
- Returns size or -1 with the error code placed into errno. The TCP/IP
- read and write functions behave like reads and writes on pipes when it
- comes to signals.
- ETH Functions
- ioctl(fd, NWIOGETHSTAT, &struct nwio_ethstat)
- The NWIOGETHSTAT ioctl returns the Ethernet address and some statistics
- of the Ethernet server of the channel fd. The result is returned in the
- nwio_ethstat structure. The struct nwio_ethstat is defined in
- <net/gen/eth_io.h>:
- typedef struct nwio_ethstat
- {
- ether_addr_t nwes_addr;
- eth_stat_t nwes_stat;
- } nwio_ethstat_t;
- typedef struct eth_stat
- {
- unsigned long ets_recvErr, /* # receive errors */
- ets_sendErr, /* # send error */
- ets_OVW, /* # buffer overwrite warnings,
- (packets arrive faster than
- can be processed) */
- ets_CRCerr, /* # crc errors of read */
- ets_frameAll, /* # frames not aligned (# bits
- not a multiple of 8) */
- ets_missedP, /* # packets missed due to too
- slow packet processing */
- ets_packetR, /* # packets received */
- ets_packetT, /* # packets transmitted */
- ets_transDef, /* # transmission deferred (there
- was a transmission of an
- other station in progress */
- ets_collision, /* # collisions */
- ets_transAb, /* # transmissions aborted due
- to excessive collisions */
- ets_carrSense, /* # carrier sense lost */
- ets_fifoUnder, /* # fifo underruns (processor
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- is too busy) */
- ets_fifoOver, /* # fifo overruns (processor is
- too busy) */
- ets_CDheartbeat, /* # times unable to transmit
- collision signal */
- ets_OWC; /* # times out of window
- collision */
- } eth_stat_t;
- ioctl(fd, NWIOSETHOPT, &struct nwio_ethopt)
- Before an Ethernet channel can be used to send or receive Ethernet
- packets, it has to be configured using the NWIOSETHOPT ioctl. The
- structure nwio_ethopt is defined in <net/gen/eth_io.h>:
- typedef struct nwio_ethopt
- {
- u32_t nweo_flags;
- ether_addr_t nweo_multi, nweo_rem;
- ether_type_t nweo_type;
- } nwio_ethopt_t;
- #define NWEO_NOFLAGS 0x0000L
- #define NWEO_ACC_MASK 0x0003L
- # define NWEO_EXCL 0x00000001L
- # define NWEO_SHARED 0x00000002L
- # define NWEO_COPY 0x00000003L
- #define NWEO_LOC_MASK 0x0010L
- # define NWEO_EN_LOC 0x00000010L
- # define NWEO_DI_LOC 0x00100000L
- #define NWEO_BROAD_MASK 0x0020L
- # define NWEO_EN_BROAD 0x00000020L
- # define NWEO_DI_BROAD 0x00200000L
- #define NWEO_MULTI_MASK 0x0040L
- # define NWEO_EN_MULTI 0x00000040L
- # define NWEO_DI_MULTI 0x00400000L
- #define NWEO_PROMISC_MASK 0x0080L
- # define NWEO_EN_PROMISC 0x00000080L
- # define NWEO_DI_PROMISC 0x00800000L
- #define NWEO_REM_MASK 0x0100L
- # define NWEO_REMSPEC 0x00000100L
- # define NWEO_REMANY 0x01000000L
- #define NWEO_TYPE_MASK 0x0200L
- # define NWEO_TYPESPEC 0x00000200L
- # define NWEO_TYPEANY 0x02000000L
- #define NWEO_RW_MASK 0x1000L
- # define NWEO_RWDATONLY 0x00001000L
- # define NWEO_RWDATALL 0x10000000L
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- The configuration is divided in a number of section (covered by the
- xx_MASK macros). Options can be set in the nweo_flags field. The first
- section (NWEO_ACC_MASK) controls the access to a certain Ethernet packet
- type. If NWEO_EXCL is selected then this is the only channel that can
- send or receive Ethernet packets of the selected type. If NWEO_SHARED is
- selected then multiple channels (which all have to select NWEO_SHARED)
- can use the same Ethernet type, they all can send packets but incoming
- packets will be delivered to at most one of them. If NWEO_COPY is
- selected then multiple channels have access to the same Ethernet type and
- all receive a copy of an incoming packet.
- The NWEO_LOC_MASK flags control the delivery of packets with a
- destination address equal to the Ethernet address of the machine. If
- NWEO_EN_LOC is selected then these packets will be delivered and with
- NWEO_DI_LOC they will be discarded.
- NWEO_BROAD_MASK, NWEO_MULTI_MASK, and NWEO_PROMISC_MASK do the same to
- broadcast packets, multicast packets and promiscuous mode packets as
- NWEO_LOC_MASK does for local packets. Except that the precise multicast
- address is taken from the nweo_multi field.
- The NWEO_REM_MASK flags control whether communication is restricted to
- single destination or not. NWEO_REMSPEC restricts sending and receiving
- of packets to the single remote computer specified in the nweo_rem field.
- NWEO_REMANY allows sending to and receiving from any remote computer.
- NWEO_TYPESPEC restricts sending and receiving of packets to the type
- specified in nweo_type. The type has to be in network byte order (using
- hton(3)). NWEO_TYPEANY allows any type.
- If the Ethernet header is completely specified by the nweo_flags i.e.,
- all of NWEO_EN_LOC, NWEO_DI_BROAD, NWEO_DI_MULTI, NWEO_DI_PROMISC,
- NWEO_REMSPEC and NWEO_TYPESPEC are specified, then NWEO_RWDATONLY can be
- used to send and receive only the data part of an Ethernet packet. If
- NWEO_RWDATALL is specified then both Ethernet header and data are used.
- PSIP Functions
- [[[No description available yet.]]]
- IP Functions
- ioctl(fd, NWIOGIPCONF, &struct nwio_ipconf)
- The NWIOGIPCONF ioctl reports the Internet Address and the netmask. For
- the nwio_ipconf structure see the NWIOSIPCONF ioctl below.
- ioctl(fd, NWIOGIPOROUTE, &struct nwio_route)
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- The NWIOGIPOROUTE ioctl can be used to query an IP server about its
- routing table. [[[NWIODIPOROUTE, NWIOGIPIROUTE, NWIODIPIROUTE?]]] The
- structure nwio_route is defined in <net/gen/route.h>:
- typedef struct nwio_route
- {
- u32_t nwr_ent_no;
- u32_t nwr_ent_count;
- ipaddr_t nwr_dest;
- ipaddr_t nwr_netmask;
- ipaddr_t nwr_gateway;
- u32_t nwr_dist;
- u32_t nwr_flags;
- u32_t nwr_pref;
- } nwio_route_t;
- #define NWRF_EMPTY 0
- #define NWRF_INUSE 1
- #define NWRF_FIXED 2
- The requested entry is taken from nwr_ent_no. Entries are counted from
- 0, so the value 0 can be used for an initial query. The size of the
- routing table is returned in nwr_ent_count. The nwr_flags indicates if
- the entry is in use (NWRF_INUSE) and if the entry was inserted manually
- (using NWIOSIPOROUTE) or generated by the IP server itself. The route is
- described by nwr_dest, nwr_netmask, nwr_gateway, nwr_dist, and nwr_pref.
- Nwr_dest and nwr_netmask select the destination addresses. A value of
- 0.0.0.0 (0x0) in both nwr_dest and nwr_netmask means every host. A value
- of 255.255.255.255 (0xffffffff) in nwr_netmask means a single host.
- Other values of nwr_netmask are netmasks for the network specified by
- nwr_dest. Nwr_gateway is gateway that should be used. Nwr_dist is a
- minimal distance. Packets with a time to live smaller than nwr_dist will
- not reach the destination. If two routes have equal netmask and distance
- fields but different gateways then the gateway with highest value in
- nwr_pref is used.
- ioctl(fd, NWIOSIPCONF, &struct nwio_ipconf)
- The NWIOSIPCONF ioctl can be used to inform the IP server about its
- Internet Address and/or its netmask. Normally an IP server will discover
- its Internet Address using the RARP protocol. NWIOSIPCONF can be used in
- the case that the RARP failed, or the netmask has to be changed. Note
- that higher level protocols (TCP and UDP) assume that the Internet
- Address of an IP device does not change, therefore TCP and UDP stop
- functioning if the Internet Address is changed.
- The structure nwio_ipconf is defined in <net/gen/ip_io.h>:
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- typedef struct nwio_ipconf
- {
- u32_t nwic_flags;
- ipaddr_t nwic_ipaddr;
- ipaddr_t nwic_netmask;
- } nwio_ipconf_t;
- #define NWIC_NOFLAGS 0x0
- #define NWIC_FLAGS 0x3
- # define NWIC_IPADDR_SET 0x1
- # define NWIC_NETMASK_SET 0x2
- The function of nwio_ipconf depends on the value of nwic_flags. If
- NWIC_IPADDR_SET is set then the Internet Address will be set to
- nwic_ipaddr. If NWIC_NETMASK_SET is set then the Internet Address will
- be set to nwic_netmask.
- ioctl(fd, NWIOSIPOPT, &struct nwio_ipopt)
- Before an IP channel can be used, it has to be configured using the
- NWIOSIPOPT ioctl. The structure nwio_ipopt is defined in
- <net/gen/ip_io.h>:
- typedef struct nwio_ipopt
- {
- u32_t nwio_flags;
- ipaddr_t nwio_rem;
- ip_hdropt_t nwio_hdropt;
- u8_t nwio_tos;
- u8_t nwio_ttl;
- u8_t nwio_df;
- ipproto_t nwio_proto;
- } nwio_ipopt_t;
- #define NWIO_NOFLAGS 0x0000L
- #define NWIO_ACC_MASK 0x0003L
- # define NWIO_EXCL 0x00000001L
- # define NWIO_SHARED 0x00000002L
- # define NWIO_COPY 0x00000003L
- #define NWIO_LOC_MASK 0x0010L
- # define NWIO_EN_LOC 0x00000010L
- # define NWIO_DI_LOC 0x00100000L
- #define NWIO_BROAD_MASK 0x0020L
- # define NWIO_EN_BROAD 0x00000020L
- # define NWIO_DI_BROAD 0x00200000L
- #define NWIO_REM_MASK 0x0100L
- # define NWIO_REMSPEC 0x00000100L
- # define NWIO_REMANY 0x01000000L
- #define NWIO_PROTO_MASK 0x0200L
- # define NWIO_PROTOSPEC 0x00000200L
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- # define NWIO_PROTOANY 0x02000000L
- #define NWIO_HDR_O_MASK 0x0400L
- # define NWIO_HDR_O_SPEC 0x00000400L
- # define NWIO_HDR_O_ANY 0x04000000L
- #define NWIO_RW_MASK 0x1000L
- # define NWIO_RWDATONLY 0x00001000L
- # define NWIO_RWDATALL 0x10000000L
- The options are divided in several categories: NWIO_ACC_MASK,
- NWIO_LOC_MASK, NWIO_BROAD_MASK, NWIO_REM_MASK, NWIO_PROTO_MASK,
- NWIO_HDR_O_MASK and NWIO_RW_MASK. A channel is configured when one
- option of each category is set.
- The options covered by NWIO_ACC_MASK control the number of channels that
- can use one IP protocol. If NWIO_EXCL is specified then only that
- channel can use a certain IP protocol. If NWIO_SHARED then multiple
- channels that all have to specify NWIO_SHARED can use the same IP
- protocol, but incoming packets will be delivered to a most one channel.
- NWIO_SHARED does not impose any restrictions. Every channel gets a copy
- of an incoming packet.
- NWIO_LOC_MASK and NWIO_BROAD_MASK control the delivery of packets. If
- NWIO_EN_LOC is specified then packets that are explicitly send to the IP
- server are delivered. If NWIO_EN_BROAD is specified then broadcast
- packets are delivered. Either one or both of them can be disabled with
- NWIO_DI_LOC and NWIO_DI_BROAD.
- NWIO_REMSPEC can be used to restrict communication to one remote host.
- This host is taken from the nwio_rem field. If any remote host is to be
- allowed then NWIO_REMANY can be used.
- NWIO_PROTOSPEC restricts communication to one IP protocol, specified in
- nwio_proto. NWIO_PROTOANY allows any protocol to be sent or received.
- NWIO_HDR_O_SPEC specifies all IP header options in advance. The values
- are taken from nwio_hdropt, nwio_tos, nwio_ttl, and nwio_df. Nwio_hdropt
- specifies the IP options that should be present in an outgoing packet.
- Ip_hdropt_t is defined in <net/gen/in.h>:
- typedef struct ip_hdropt
- {
- u8_t iho_opt_siz;
- u8_t iho_data[IP_MAX_HDR_SIZE-IP_MIN_HDR_SIZE];
- } ip_hdropt_t;
- The bytes of size iho_opt_siz in iho_data are appended to the IP header.
- Nwio_tos specifies the value of the ``type of service'' bits, nwio_ttl
- gives the value of the ``time to live'' field and nwio_df specifies
- whether fragmentation is disallowed or not. NWIO_HDR_O_ANY specifies
- that the header options should be specified at each write request.
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- IP(4) Minix Programmer's Manual IP(4)
- NWIO_RWDATONLY specifies that the header should be omitted from a write
- request. This option can only be used when all header fields are
- specified in previous options: NWIO_EN_LOC, NWIO_DI_BROAD, NWIO_REMSPEC,
- NWIO_PROTOSPEC and NWIO_HDR_O_SPEC. A read operation will also only
- return the data part, so the IP options will be lost.
- ioctl(fd, NWIOSIPOROUTE, &struct nwio_route)
- The NWIOSIPOROUTE ioctl adds a route to the routing table. See
- NWIOGIPOROUTE above for a description of the nwio_route structure. The
- fields nwr_ent_no and nwr_ent_count are ignored.
- TCP Functions
- ioctl(fd, NWIOTCPCONN, &struct nwio_tcpcl)
- The NWIOTCPCONN ioctl tries to setup a connection with a remote TCP/IP
- server. The channel must be fully configured (see NWIOSTCPCONF) and
- values for the local port, the remote port and the remote address have be
- specified using NWTC_LP_SET or NWTC_LP_SEL, NWTC_SET_RA and NWTC_SET_RP.
- The struct nwio_tcpcl is defined in <net/gen/tcp_io.h> as:
- typedef struct nwio_tcpcl
- {
- long nwtcl_flags;
- long nwtcl_ttl;
- } nwio_tcpcl_t;
- Set the nwtcl_flags field to zero before the connect or listen call.
- [[[Further explanation of nwio_tcpcl?]]]
- ioctl(fd, NWIOGTCPCONF, &struct nwio_tcpconf)
- This call reports the current configuration of a TCP channel. The
- nwtc_flags field shows the status of the access, locport, remaddr and
- remport fields. Nwtc_locaddr contains the Internet address of the TCP/IP
- server. Remaddr contains the Internet address of the remote TCP/IP
- server when set with NWTC_SET_RA or after a successful connect or listen
- (see NWIOTCPCONN or NWIOTCPLISTEN). Nwio_locport contains the local
- TCP/IP port set with NWTC_LP_SET or the selected port set with
- NWTC_LP_SEL. Nwtc_remport contains the TCP port of the remote TCP/IP
- server as set with NWIO_SET_RP or after a successful connect or listen.
- A value of 0 (zero) is reported for nwtc_remaddr, nwtc_locport or
- nwtc_remport when no value is set either explicitly or implicitly.
- ioctl(fd, NWIOTCPLISTEN, &struct nwio_tcpcl)
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- The NWIOTCPLISTEN ioctl waits until a remote TCP/IP server tries to
- connect to this channel. The channel has to be configured (see
- NWIOSTCPCONF). An additional restriction is that the local port must be
- set (with NWTC_LP_SET) or selected (with NWTC_LP_SEL). When a remote
- address is set only connections for that host are accepted, and when a
- remote port is set only connections from that port are accepted. After a
- successful listen NWIOGTCPCONF can be used to find out what the address
- and port of the other side are.
- ioctl(fd, NWIOSTCPCONF, &struct nwio_tcpconf)
- Before a TCP channel can be used it must configured using the
- NWIOSTCPCONF ioctl. The parameters to NWIOSTCPCONF are the channel file
- descriptor and a struct nwio_tcpconf as defined in <net/gen/tcp_io.h>:
- typedef struct nwio_tcpconf
- {
- u32_t nwtc_flags;
- ipaddr_t nwtc_locaddr;
- ipaddr_t nwtc_remaddr;
- tcpport_t nwtc_locport;
- tcpport_t nwtc_remport;
- } nwio_tcpconf_t;
- #define NWTC_NOFLAGS 0x0000L
- #define NWTC_ACC_MASK 0x0003L
- # define NWTC_EXCL 0x00000001L
- # define NWTC_SHARED 0x00000002L
- # define NWTC_COPY 0x00000003L
- #define NWTC_LOCPORT_MASK 0x0030L
- # define NWTC_LP_UNSET 0x00000010L
- # define NWTC_LP_SET 0x00000020L
- # define NWTC_LP_SEL 0x00000030L
- #define NWTC_REMADDR_MASK 0x0100L
- # define NWTC_SET_RA 0x00000100L
- # define NWTC_UNSET_RA 0x01000000L
- #define NWTC_REMPORT_MASK 0x0200L
- # define NWTC_SET_RP 0x00000200L
- # define NWTC_UNSET_RP 0x02000000L
- A tcp channel is considered configured when one flag in each category has
- been selected. Thus one of NWTC_EXCL, NWTC_SHARED or NWTC_COPY, one of
- NWTC_LP_UNSET, NWTC_LP_SET or NWTC_LP_SEL, one of NWTC_SET_RA or
- NWTC_UNSET_RA, and one of NWTC_SET_RP or NWTC_UNSET_RP.
- The acc flags control the access to a certain TCP port. NWTC_EXCL means
- exclusive access. An attempt to configure a channel will be denied if
- the same port is specified as that of a channel that requested exclusive
- access. NWTC_SHARED indicates that several channels use the same port
- but cooperate. If the shared mode is specified for one channel than all
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- other channel that use the same port should also be configured with the
- NWTC_SHARED flag. NWTC_COPY is specified when the programmer does not
- care about other channels. This is the default.
- The locport flags control which TCP port is used for communication.
- NWTC_LP_UNSET indicates the absence of a local port. This is the
- default. NWTC_LP_SET means that the nwtc_locport field contains the
- local port to be used by TCP. This value must be in network byte order
- (see hton(3).) NWTC_LP_SEL requests the TCP server to pick a port. This
- port will be in the range from 32768 to 65535 and will be unique.
- The remaddr flags specify which hosts are acceptable for connections.
- NWTC_SET_RA indicates that only connection to the host specified in
- nwtc_remaddr are acceptable. Nwtc_remaddr should be in network byte
- order (see hton(3).) NWTC_UNSET_RA allows every host on the other side
- of a connection. This is the default.
- The remport flags specify which remote ports are acceptable for
- connections. NWTC_SET_RP indicates that only the port specified in
- nwtc_remport is acceptable. NWTC_UNSET_RP allows every port on the other
- side of a connection. This is the default.
- ioctl(fd, NWIOTCPSHUTDOWN)
- The NWIOTCPSHUTDOWN tells the TCP/IP server that no more data will be
- sent over the channel specified by fd. This command can be issued when
- the channel is connected to a remote TCP/IP server. The TCP/IP server
- will tell the remote TCP/IP server and the client of the remote TCP/IP
- server will receive an end-of-file indication.
- ioctl(fd, NWIOGTCPOPT, &struct nwio_tcpopt)
- ioctl(fd, NWIOSTCPOPT, &struct nwio_tcpopt)
- The behaviour of a TCP channel may be changed by setting a number of
- options. The TCP options can be obtained with the NWIOGTCPOPT ioctl and
- set with the NWIOSTCPOPT ioctl. The options are passed in a struct
- nwio_tcpopt as defined in <net/gen/tcp_io.h>:
- typedef struct nwio_tcpopt
- {
- u32_t nwto_flags;
- } nwio_tcpconf_t;
- #define NWTO_NOFLAG 0x0000L
- #define NWTO_SND_URG_MASK 0x0001L
- # define NWTO_SND_URG 0x00000001L
- # define NWTO_SND_NOTURG 0x00010000L
- #define NWTO_RCV_URG_MASK 0x0002L
- # define NWTO_RCV_URG 0x00000002L
- # define NWTO_RCV_NOTURG 0x00020000L
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- #define NWTO_BSD_URG_MASK 0x0004L
- # define NWTO_BSD_URG 0x00000004L
- #define NWTO_DEL_RST_MASK 0x0008L
- # define NWTO_DEL_RST 0x00000008L
- The NWTO_SND_URG option causes bytes written to the channel to be send
- out as urgent data. On receiving an EURG error the NWTO_RCV_URG option
- must be set to switch over to reading urgent data. When all urgent data
- has been read an ENOURG error will follow, indicating that the option
- must be cleared with NWTO_RCV_NOTURG. Alas the BSD implementation of
- urgent data disagrees with the RFC's, so to be BSD compatible one must
- set the NWTO_BSD_URG option beforehand on a channel that is to send or
- receive urgent data. Given that the BSD implementation is the regarded
- as the TCP/IP standard one should always use the BSD style. The
- NWTO_DEL_RST option delays a failure response on a connect to the same
- port as the current open connection. Without this option a connect would
- fail if a server is not yet listening. With this option a connect will
- linger on until the server starts listening. This option is useful for a
- server that opens a connection, tells the remote end the local port
- number and then listens (FTP), or for a program that forks off servers
- for incoming connections (TELNET). A new connection may come in before a
- new listen can be started, so it is nice if the new connect doesn't fail.
- Use this option only when it is clearly needed.
- UDP Functions
- ioctl(fd, NWIOGUDPOPT, &struct nwio_udpopt)
- The NWIOGUDPOPT ioctl returns the current options that result from the
- default options and the options set with NWIOSUDPOPT. When NWUO_LP_SEL
- or NWUO_LP_SET is selected the local port is returned in nwuo_locport.
- When NWUO_RP_SET is selected the remote port is returned in nwuo_remport.
- The local address is always returned in nwuo_locaddr, and when
- NWUO_RA_SET is selected the remote address is returned in nwuo_remaddr.
- ioctl(fd, NWIOSUDPOPT, &struct nwio_udpopt)
- A UDP channel must be configured using the NWIOSUDPOPT ioctl before any
- data can be read or written. NWIOSUDPOPT takes two parameters, a file
- descriptor to an open UDP device and pointer to a nwio_udpopt structure
- that describes the requested configuration. The nwio_udpopt structure is
- defined in <net/gen/udp_io.h> as:
- typedef struct nwio_udpopt
- {
- unsigned long nwuo_flags;
- udpport_t nwuo_locport;
- udpport_t nwuo_remport;
- ipaddr_t nwuo_locaddr;
- ipaddr_t nwuo_remaddr;
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- } nwio_udpopt_t;
- #define NWUO_NOFLAGS 0x0000L
- #define NWUO_ACC_MASK 0x0003L
- #define NWUO_EXCL 0x00000001L
- #define NWUO_SHARED 0x00000002L
- #define NWUO_COPY 0x00000003L
- #define NWUO_LOCPORT_MASK 0x000CL
- #define NWUO_LP_SEL 0x00000004L
- #define NWUO_LP_SET 0x00000008L
- #define NWUO_LP_ANY 0x0000000CL
- #define NWUO_LOCADDR_MASK 0x0010L
- #define NWUO_EN_LOC 0x00000010L
- #define NWUO_DI_LOC 0x00100000L
- #define NWUO_BROAD_MASK 0x0020L
- #define NWUO_EN_BROAD 0x00000020L
- #define NWUO_DI_BROAD 0x00200000L
- #define NWUO_REMPORT_MASK 0x0100L
- #define NWUO_RP_SET 0x00000100L
- #define NWUO_RP_ANY 0x01000000L
- #define NWUO_REMADDR_MASK 0x0200L
- #define NWUO_RA_SET 0x00000200L
- #define NWUO_RA_ANY 0x02000000L
- #define NWUO_RW_MASK 0x1000L
- #define NWUO_RWDATONLY 0x00001000L
- #define NWUO_RWDATALL 0x10000000L
- #define NWUO_IPOPT_MASK 0x2000L
- #define NWUO_EN_IPOPT 0x00002000L
- #define NWUO_DI_IPOPT 0x20000000L
- A UDP channel is considered configured when one flag in each category has
- been selected. Thus one of NWUO_EXCL, NWUO_SHARED or NWUO_COPY, one of
- NWUO_LP_SEL, NWUO_LP_SET or NWUO_LP_ANY, one of NWUO_EN_LOC or
- NWUO_DI_LOC, one of NWUO_EN_BROAD, or NWUO_DI_BROAD, one of NWUO_RP_SET,
- or NWUO_RP_ANY, one of NWUO_RA_SET, or NWUO_RA_ANY, one of
- NWUO_RWDATONLY, or NWUO_RWDATALL, and one of NWUO_EN_IPOPT, or
- NWUO_DI_IPOPT. The acc flags control the access to a certain UDP port.
- NWUO_EXCL means exclusive access: no other channel can use this port.
- NWUO_SHARED means shared access: only channels that specify shared
- access can use this port and all packets that are received are handed to
- at most one channel. NWUO_COPY imposes no access restriction and all
- channels get a copy of every received packet for that port.
- The locport flags control the selection of the UDP port for this channel.
- NWUO_LP_SEL requests the server to pick a port. This port will be in the
- range from 32768 to 65535 and it will be unique. NWUO_LP_SET sets the
- local port to the value of the nwuo_locport field. NWUO_LP_ANY does not
- select a port. Reception of data is therefore not possible but it is
- possible to send data. (See tcpip_read, and tcpip_write above).
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- The locaddr flags control the reception of packets. NWUO_EN_LOC enables
- the reception of packets with the local IP address as destination.
- NWUO_DI_LOC disables the reception of packet for the local IP address.
- The broad flags control the reception of broadcast packets.
- NWUO_EN_BROAD enables the reception of broadcast packets and
- NWUO_DI_BROAD disables the reception of broadcast packets.
- The remport flags let the client to specify one specific remote UDP port
- or to allow any remote port. NWUO_RP_SET sets the remote UDP port to the
- value of nwuo_remport. Only packets with a matching remote port will be
- delivered and all packets will be sent to that port. NWUO_RP_ANY allows
- reception of packets form any port and when transmitting packets the
- remote port has to be specified.
- The remaddr flags control the remote IP address. NWUO_RA_SET sets the
- remote IP address the value of nwuo_remaddr. Only packets from that
- address will be delivered and all packets will be sent to that address.
- NWUO_RA_ANY allows reception of packets from any host and when
- transmitting packets the remote host has to be specified.
- The rw flags control the format of the data to be sent or received. With
- NWUO_RWDATONLY only the data part of a UDP packet is sent to the server
- and only the data part is received from the server. The NWUO_RWDATALL
- mode presents the data part of a UDP packet with a header that contains
- the source and destination IP address, source and destination UDP ports,
- the IP options, etc. The server expects such a header in front of the
- data to be transmitted.
- The ipopt flags control the delivery and transmission of IP options.
- When NWUO_EN_IPOPT is set IP, options will be delivered and sent. When
- NWUO_DI_IPOPT is set IP option will be stripped from received packets and
- no IP options will be sent.
- FILES
- /dev/eth[01] First and second raw ethernet.
- /dev/psip[01] First and second Pseudo IP network.
- /dev/ip[0123] IP devices for two ethernets and two Pseudo IP
- networks.
- /dev/tcp[0123] TCP devices for same four networks.
- /dev/udp[0123] UDP devices.
- /dev/eth, /dev/psip, /dev/ip, /dev/tcp, /dev/udp
- Devices for the default network, links to the devices
- above. Eth is only present if ethernet is the default,
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- psip only for pseudo IP.
- SEE ALSO
- hton(3), oneC_sum(3), set_net_default(8), boot(8).
- DIAGNOSTICS
- Several errors may be returned by the TCP/IP server. The error code is
- found in the errno variable if the read, write, or ioctl call returns -1.
- The TCP/IP error codes defined in <errno.h> are:
- EPACKSIZE This indicates an attempt to read or write with a
- buffer that is too large or too small.
- EOUTOFBUFS The TCP/IP server has insufficient memory to
- execute the request.
- EBADIOCTL This indicates an attempt to execute a command the
- particular server does not understand. For
- example, a NWIOGTCPCONF on an ETH channel.
- EBADMODE The request is refused because the channel is not
- fully configured, in the wrong state or the
- parameters are invalid.
- EBADDEST This indicates an illegal destination address for
- a packet.
- EDSTNORCH The destination is not reachable.
- EISCONN The channel is already connected so a second
- request is refused.
- EADDRINUSE This address is in use.
- ECONNREFUSED The connection is refused by the other side.
- ECONNRESET The connection is reset (non-gracefully
- terminated) by the other side.
- ETIMEDOUT The connection is terminated due to an expired
- timer.
- EURG Urgent data is present and the current receive
- mode does not allow urgent data to be transferred.
- ENOURG No urgent data is present and a request came for
- urgent data.
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- IP(4) Minix Programmer's Manual IP(4)
- ENOTCONN The request requires a connected channel and the
- channel is not connected.
- ESHUTDOWN The connection is shut down. That is, a
- NWIOTCPSHUTDOWN has been executed so no more data
- can be transmitted.
- ENOCONN The connection does not exist.
- EGENERIC A generic error code for extremely weird cases.
- AUTHOR
- Philip Homburg (philip@cs.vu.nl)
- 16
English
