functions to query and parse SPF entries More...

#include <qsmtpd/antispam.h>
#include <fmt.h>
#include <libowfatconn.h>
#include <match.h>
#include <mime_chars.h>
#include <netio.h>
#include <qsmtpd/qsmtpd.h>
#include <sstring.h>
#include <arpa/inet.h>
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <netinet/in.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

Macros
#define	_GNU_SOURCE /* for strcasestr() */

#define	WRITEl(fd, s, l) if ( (rc = write((fd), (s), (l))) < 0 ) return rc

#define	WRITE(fd, s) WRITEl((fd), (s), strlen(s))

#define	APPEND(addlen, addstr)

#define	PARSEERR do { free(*res); return -SPF_PERMERROR; } while (0)

#define	APPEND(addlen, addstr)

Enumerations
enum	spf_makro_expansion { SPF_MAKRO_NONE, SPF_MAKRO_PERCENT, SPF_MAKRO_BRACE, SPF_MAKRO_LETTER, SPF_MAKRO_TRANSFORMER, SPF_MAKRO_DELIMITER }

Functions
int	spfreceived (int fd, const int spf)

static int	spf_makroparam (const char token, int num, int r, int delim)

static int	urlencode (const char token, char *result)
	URL-encode a given string. More...

static int	spf_appendmakro (char *res, unsigned int l, const char *const s, const unsigned int sl, int num, const int r, const int delim)

static int	validate_domain (char ***domainlist)

static int	spf_makroletter (const char p, const char domain, int ex, char *res, unsigned int l)

int	spf_makro (const char token, const char domain, int ex, char **result)

static int	spf_domainspec (const char domain, const char token, char *domainspec, int ip4cidr, int *ip6cidr)
	parse the domainspec More...

static int	may_have_domainspec (const char *token)
	check if a domainspec is present More...

static int	spfmx (const char domain, const char token)

static int	spfa (const char domain, const char token)

static int	spfexists (const char domain, const char token)

static int	spfptr (const char domain, const char token)

static int	spfip4 (const char *domain)

static int	spfip6 (const char *domain)

static int	txtlookup (char *txt, const char domain)
	lookup TXT record taking SPF specialities into account More...

static size_t	match_mechanism (const char token, const char mechanism, const char *delimiters)
	check if the token matches the given mechanism More...

static size_t	spf_modifier_name (const char *token)

static void	record_bad_token (const char *token)

static const char *	find_modifier (const char s, const char mod)
	find the given modifier in the given string More...

static int	spflookup (const char domain, unsigned int queries)

int	check_host (const char *domain)

Variables
static const char	spf_delimiters [] = ".-+,/_="

Detailed Description

functions to query and parse SPF entries

Macro Definition Documentation

#define APPEND	(	addlen,
		addstr
	)

Value:

{\
                char *r2;\
                unsigned int oldl = *l;\
                \
                *l += addlen;\
                r2 = realloc(*res, *l);\
                if (!r2) { free(*res); return -1;}\
                *res = r2;\
                memcpy(*res + oldl, addstr, addlen);\
        }

#define APPEND	(	addlen,
		addstr
	)

Value:

{\
                char *r2;\
                unsigned int oldl = l;\
                \
                l += addlen;\
                r2 = realloc(res, l);\
                if (!r2) { free(res); return -1;}\
                res = r2;\
                memcpy(res + oldl, addstr, addlen);\
        }

Function Documentation

int check_host ( const char * domain )

look up SPF records for domain

This works a like the check_host in the SPF draft but takes two arguments less. The remote ip and the full sender address can be taken directly from xmitstat.

Parameters

domain no idea what this might be for ;)

Returns: one of the SPF_* constants defined in include/antispam.h

static const char* find_modifier	(	const char *	s,
		const char *	mod
	)

static

find the given modifier in the given string

Parameters

s	the string to search
mod	the modifier to search

Returns: the first modifier match

Return values

NULL	modifier was not found

static size_t match_mechanism	(	const char *	token,
		const char *	mechanism,
		const char *	delimiters
	)

static

check if the token matches the given mechanism

Parameters

token	current token to match
mechanism	the mechanism string to match
delimiters	the delimiters that may be present after the token

Returns: length of the matched mechanism on success

Return values

0	mechanism did not match

static int may_have_domainspec ( const char * token )

static

check if a domainspec is present

Parameters

token the token to check

Returns: if domainspec is present

Return values

0	no domainspec present
1	domainspec is present
-SPF_PERMERROR	invalid characters detected

This does not check the domainspec itself, it only checks if one is given.

static void record_bad_token ( const char * token )

static

write the bad token to the SPF explanation record

Parameters

token the current token string

static int spf_appendmakro	(	char **	res,
		unsigned int *	l,
		const char *const	s,
		const unsigned int	sl,
		int	num,
		const int	r,
		const int	delim
	)

static

append a makro content to the result

Parameters

res	result string
l	current length of res
s	the raw string to appended, does not need to be terminated by '\0'
sl	strlen(s), must not be 0
num	DIGIT
r	Bit 1: reverse of not; Bit 2: use URL encoding
delim	bit mask of delimiters

Returns: 0 on success, -1 on error

static int spf_domainspec	(	const char *	domain,
		const char *	token,
		char **	domainspec,
		int *	ip4cidr,
		int *	ip6cidr
	)

static

parse the domainspec

Parameters

domain	the current domain string
token	pointer to the string after the token
domainspec	here the expanded domain string is stored (memory will be malloced)
ip4cidr	the length of the IPv4 net (parsed if present in token, -1 if none given)
ip6cidr	same for IPv6 net length

Returns: if domainspec is valid or not

Return values

-1	error (ENOMEM)
SPF_PERMERROR	domainspec is syntactically invalid
0	everything is fine, domainspec is set

int spf_makro	(	const char *	token,
		const char *	domain,
		int	ex,
		char **	result
	)

expand a SPF makro

Parameters

token	the token to parse
domain	the current domain string
ex	if this is an exp string
result	the resulting string is stored here

Returns: if makro is valid or not

Return values

0	makro is valid, result is set
-1	internal error (ENOMEM)
SPF_PERMERROR	syntax error

not static, is called from targets/testspf.c

static int spf_makroletter	(	const char *	p,
		const char *	domain,
		int	ex,
		char **	res,
		unsigned int *	l
	)

static

expand a SPF makro letter

Parameters

p	the token to parse
domain	the current domain string
ex	if this is an exp string
res	the resulting string is stored here
l	offset into res

Returns: number of bytes parsed, -1 on error

static int spf_makroparam	(	const char *	token,
		int *	num,
		int *	r,
		int *	delim
	)

static

parse the options in an SPF macro

Parameters

token	token to parse
num	DIGIT
r	if reverse is given
delim	bitmask of delimiters

Returns: number of bytes parsed, -1 on error

static size_t spf_modifier_name ( const char * token )

static

check if the given token is a valid SPF modifier-name

Parameters

token the token to parse

Returns: the length of the modifier-name, i.e. the position of the terminating '='

Return values

0	the given token is no valid modifier-name

static int spflookup	(	const char *	domain,
		unsigned int *	queries
	)

static

look up SPF records for domain

Parameters

domain	no idea what this might be for
queries	number of DNS queries done

Returns: one of the SPF_* constants defined in include/antispam.h or -1 on ENOMEM

int spfreceived	(	int	fd,
		const int	spf
	)

print "Received-SPF:" to message header

Parameters

fd	file descriptor of message body
spf	SPF status of mail transaction

Returns: 0 if everything goes right, -1 on write error

static int txtlookup	(	char **	txt,
		const char *	domain
	)

static

lookup TXT record taking SPF specialities into account

Parameters

txt	result pointer
domain	domain token to look up

Returns: the same error codes as dnstxt()

This will take two SPF specific contraints into account:

trailing dots are ignored
if domain is longer than 253 characters parts are removed until it is shorter

static int urlencode	(	const char *	token,
		char **	result
	)

static

URL-encode a given string.

Parameters

token	the token to encode
result	storage of the result

Returns: if the conversion was successful

Return values

0	the string was recoded
1	the string does not need to be recoded
-1	memory allocation error

static int validate_domain ( char *** domainlist )

static

build a list of validated domain names for the connected host

Parameters

domainlist where to store the array

Returns: how many entries are in domainlist, negative on error

If this functions returns 0 all lookups were successfully, but no validated domain names were found.

Macros

Enumerations

Functions

Variables

Detailed Description

Macro Definition Documentation

Function Documentation