Add support for decoding the type of a cmsg.

lib/libsysdecode/Makefile

@@ -15,6 +15,7 @@ CFLAGS+= -I${SRCTOP}/libexec/rtld-elf
 MAN=	sysdecode.3 \
 	sysdecode_abi_to_freebsd_errno.3 \
 	sysdecode_cap_rights.3 \
+	sysdecode_cmsg_type.3 \
 	sysdecode_enum.3 \
 	sysdecode_fcntl_arg.3 \
 	sysdecode_kevent.3 \

lib/libsysdecode/flags.c

@@ -1159,6 +1159,46 @@ sysdecode_cap_rights(FILE *fp, cap_rights_t *rightsp)
 	}
 }
 
+static struct name_table cmsgtypeip[] = {
+	X(IP_RECVDSTADDR) X(IP_RECVTTL) X(IP_RECVOPTS) X(IP_RECVRETOPTS)
+	X(IP_RECVIF) X(IP_RECVTOS) X(IP_FLOWID) X(IP_FLOWTYPE)
+	X(IP_RSSBUCKETID) XEND
+};
+
+static struct name_table cmsgtypeipv6[] = {
+#if 0
+	/* The RFC 2292 defines are kernel space only. */
+	X(IPV6_2292PKTINFO) X(IPV6_2292HOPLIMIT) X(IPV6_2292HOPOPTS)
+	X(IPV6_2292DSTOPTS) X(IPV6_2292RTHDR) X(IPV6_2292NEXTHOP)
+#endif
+	X(IPV6_PKTINFO)  X(IPV6_HOPLIMIT) X(IPV6_HOPOPTS)
+	X(IPV6_DSTOPTS) X(IPV6_RTHDR) X(IPV6_NEXTHOP)
+	X(IPV6_TCLASS) X(IPV6_FLOWID) X(IPV6_FLOWTYPE) X(IPV6_RSSBUCKETID)
+	X(IPV6_PATHMTU) X(IPV6_RTHDRDSTOPTS) X(IPV6_USE_MIN_MTU)
+	X(IPV6_DONTFRAG) X(IPV6_PREFER_TEMPADDR) XEND
+};
+
+static struct name_table cmsgtypesctp[] = {
+	X(SCTP_INIT) X(SCTP_SNDRCV) X(SCTP_EXTRCV) X(SCTP_SNDINFO)
+	X(SCTP_RCVINFO) X(SCTP_NXTINFO) X(SCTP_PRINFO) X(SCTP_AUTHINFO)
+	X(SCTP_DSTADDRV4) X(SCTP_DSTADDRV6) XEND
+};
+
+const char *
+sysdecode_cmsg_type(int cmsg_level, int cmsg_type)
+{
+
+	if (cmsg_level == SOL_SOCKET)
+		return (lookup_value(cmsgtypesocket, cmsg_type));
+	if (cmsg_level == IPPROTO_IP)
+		return (lookup_value(cmsgtypeip, cmsg_type));
+	if (cmsg_level == IPPROTO_IPV6)
+		return (lookup_value(cmsgtypeipv6, cmsg_type));
+	if (cmsg_level == IPPROTO_SCTP)
+		return (lookup_value(cmsgtypesctp, cmsg_type));
+	return (NULL);
+}
+
 const char *
 sysdecode_sctp_pr_policy(int policy)
 {

lib/libsysdecode/mktables

@@ -158,6 +158,7 @@ gen_table "umtxcvwaitflags" "CVWAIT_[A-Z_]+[[:space:]]+0x[0-9]+"           "sys/
 gen_table "umtxrwlockflags" "URWLOCK_PREFER_READER[[:space:]]+0x[0-9]+"    "sys/umtx.h"
 gen_table "caprights"       "CAP_[A-Z_]+[[:space:]]+CAPRIGHT\([0-9],[[:space:]]+0x[0-9]{16}ULL\)"   "sys/capsicum.h"
 gen_table "sctpprpolicy"    "SCTP_PR_SCTP_[A-Z_]+[[:space:]]+0x[0-9]+"     "netinet/sctp_uio.h" "SCTP_PR_SCTP_ALL"
+gen_table "cmsgtypesocket"  "SCM_[A-Z_]+[[:space:]]+0x[0-9]+"              "sys/socket.h"
 if [ -e "${include_dir}/x86/sysarch.h" ]; then
 	gen_table "sysarchnum" "(AMD64|I386)_[A-Z86_]+[[:space:]]+[0-9]+"  "x86/sysarch.h"
 else

lib/libsysdecode/sysdecode.3

@@ -73,6 +73,7 @@ A placeholder for use when the ABI is not known.
 .Sh SEE ALSO
 .Xr sysdecode_abi_to_freebsd_errno 3 ,
 .Xr sysdecode_cap_rights 3 ,
+.Xr sysdecode_cmsg_type 3 ,
 .Xr sysdecode_enum 3 ,
 .Xr sysdecode_fcntl_arg 3 ,
 .Xr sysdecode_ioctlname 3 ,

lib/libsysdecode/sysdecode.h

@@ -46,6 +46,7 @@ const char *sysdecode_atfd(int _fd);
 bool	sysdecode_atflags(FILE *_fp, int _flags, int *_rem);
 bool	sysdecode_cap_fcntlrights(FILE *_fp, uint32_t _rights, uint32_t *_rem);
 void	sysdecode_cap_rights(FILE *_fp, cap_rights_t *_rightsp);
+const char *sysdecode_cmsg_type(int _cmsg_level, int _cmsg_type);
 const char *sysdecode_extattrnamespace(int _namespace);
 const char *sysdecode_fadvice(int _advice);
 void	sysdecode_fcntl_arg(FILE *_fp, int _cmd, uintptr_t _arg, int _base);

lib/libsysdecode/sysdecode_cmsg_type.3

@@ -0,0 +1,54 @@
+.\"
+.\" Copyright (c) 2018 Michael Tuexen <tuexen@FreeBSD.org>
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd January 15, 2018
+.Dt sysdecode_cmsg_type 3
+.Os
+.Sh NAME
+.Nm sysdecode_cmsg_type
+.Nd lookup name of cmsg type
+.Sh LIBRARY
+.Lb libsysdecode
+.Sh SYNOPSIS
+.In sys/types.h
+.In stdbool.h
+.In sysdecode.h
+.Ft const char *
+.Fn sysdecode_cmsg_type "int cmsg_level" "int cmsg_type"
+.Sh DESCRIPTION
+The
+.Fn sysdecode_cmsg_type
+function returns a text description of the
+.Fa cmsg_type
+member of a
+.Vt struct cmsghdr .
+.Fn sysdecode_cmsg_type
+also takes the
+.Fa cmsg_level
+to uniquely identify the type.
+.Sh SEE ALSO
+.Xr sysdecode 3