On Fri, Sep 17, 2021 at 8:13 AM Alejandro Colomar <colomar.6.4.3@xxxxxxxxx> wrote: > > Hi, > > Reading a stackoverflow question > <https://stackoverflow.com/questions/51996808/do-we-need-to-specify-protocol-when-type-is-sock-dgram-or-sock-stream-in-soc> > it noted that, while ip(7) notes that protocol can be left as 0 for both > SOCK_STREAM and SOCK_DGRAM, ipv6(7) is misleading and seems to suggest > that protocol may be significant for SOCK_DGRAM (at least in the SYNOPSIS). It can be left as 0, but, I think, IPPROTO_UDPLITE (at least) can be specified in both cases, if the caller wishes so (as well as IPPROTO_MPTCP/IPPROTO_SCTP for SOCK_STREAM, and some other, more obscure protocols, like DCCP or L2TP). > I guess that's not true, and it can be left as 0, but since I don't > know, I'll ask. > > Thanks, > > Alex > > > -- > > IP(7) Linux Programmer's Manual IP(7) > > NAME > ip - Linux IPv4 protocol implementation > > SYNOPSIS > #include <sys/socket.h> > #include <netinet/in.h> > #include <netinet/ip.h> /* superset of previous */ > > tcp_socket = socket(AF_INET, SOCK_STREAM, 0); > udp_socket = socket(AF_INET, SOCK_DGRAM, 0); > raw_socket = socket(AF_INET, SOCK_RAW, protocol); > > > -- > > IPV6(7) Linux Programmer's Manual IPV6(7) > > NAME > ipv6 - Linux IPv6 protocol implementation > > SYNOPSIS > #include <sys/socket.h> > #include <netinet/in.h> > > tcp6_socket = socket(AF_INET6, SOCK_STREAM, 0); > raw6_socket = socket(AF_INET6, SOCK_RAW, protocol); > udp6_socket = socket(AF_INET6, SOCK_DGRAM, protocol); > > > -- > Alejandro Colomar > Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/ > http://www.alejandro-colomar.es/ -- Eugene Syromyatnikov mailto:evgsyr@xxxxxxxxx xmpp:esyr@jabber.{ru|org}
