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tlvs: add methods for decodemsg utility
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fixup printing methods in devtools/decodemsg such that TLV's can
now be printed as well. here's how you'd use it:

   $ ./devtools/decodemsg --tlv opening_tlv 0120001E020202020202020202020202020202020202020202020202020202020202
   > WIRE_OPTION_UPFRONT_SHUTDOWN_SCRIPT (size 32):
   > shutdown_scriptpubkey=[020202020202020202020202020202020202020202020202020202020202]
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@niftynei
niftynei committed Apr 5, 2019
1 parent f894c7a commit 6e8da57
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Showing 2 changed files with 139 additions and 40 deletions.
8 changes: 8 additions & 0 deletions devtools/decodemsg.c
View file
Expand Up @@ -12,10 +12,14 @@ int main(int argc, char *argv[])
{
const u8 *m;
bool onion = false;
char *tlv_name = NULL;
setup_locale();

opt_register_noarg("--onion", opt_set_bool, &onion,
"Decode an error message instead of a peer message");
opt_register_arg("--tlv", opt_set_charp, opt_show_charp,
&tlv_name,
"Deocde a TLV of this type instead of a peer message");
opt_register_noarg("--help|-h", opt_usage_and_exit,
"[<hexmsg>]"
"Decode a lightning spec wire message from hex, or a series of messages from stdin",
Expand All @@ -33,6 +37,8 @@ int main(int argc, char *argv[])

if (onion)
printonion_type_message(m);
else if (tlv_name)
print_tlv_message(tlv_name, m);
else
printwire_type_message(m);
} else {
Expand All @@ -55,6 +61,8 @@ int main(int argc, char *argv[])
m = tal_dup_arr(f, u8, f + off, be16_to_cpu(len), 0);
if (onion)
printonion_type_message(m);
else if (tlv_name)
print_tlv_message(tlv_name, m);
else
printwire_type_message(m);
off += be16_to_cpu(len);
Expand Down
171 changes: 131 additions & 40 deletions tools/generate-wire.py
View file
Expand Up @@ -293,20 +293,23 @@ def _guess_type(message, fieldname, base_size):

printwire_header_templ = """void printwire_{name}(const char *fieldname, const u8 *cursor);
"""
printwire_impl_templ = """void printwire_{name}(const char *fieldname, const u8 *cursor)
{{
\tsize_t plen = tal_count(cursor);

printwire_toplevel_tmpl = """\tsize_t plen = tal_count(cursor);
\tif (fromwire_u16(&cursor, &plen) != {enum.name}) {{
\t\tprintf("WRONG TYPE?!\\n");
\t\treturn;
\t}}
\t}}"""

{subcalls}
printwire_impl_templ = """{is_internal}void printwire_{name}(const char *fieldname, const u8 *{cursor_ptr}cursor{tlv_args})
{{
{toplevel_msg_setup}{subcalls}{lencheck}
}}
"""

printwire_lencheck = """
\tif (plen != 0)
\t\tprintf("EXTRA: %s\\n", tal_hexstr(NULL, cursor, plen));
}}
"""


Expand Down Expand Up @@ -707,43 +710,50 @@ def print_towire(self, is_header, tlv_name):
subcalls=str(subcalls),
)

def add_truncate_check(self, subcalls):
def add_truncate_check(self, subcalls, ref):
# Report if truncated, otherwise print.
subcalls.append('if (!cursor) {\n'
'printf("**TRUNCATED**\\n");\n'
'return;\n'
'}')
call = 'if (!{}cursor) {{\nprintf("**TRUNCATED**\\n");\nreturn;\n}}'.format(ref)
subcalls.append(call)

def print_printwire_array(self, subcalls, basetype, f, num_elems):
def print_printwire_array(self, subcalls, basetype, f, num_elems, ref):
truncate_check_ref = '' if ref else '*'
if f.has_array_helper():
subcalls.append('printwire_{}_array(tal_fmt(NULL, "%s.{}", fieldname), &cursor, &plen, {});'
.format(basetype, f.name, num_elems))
subcalls.append('printwire_{}_array(tal_fmt(NULL, "%s.{}", fieldname), {}cursor, {}plen, {});'
.format(basetype, f.name, ref, ref, num_elems))
else:
subcalls.append('printf("[");')
subcalls.append('for (size_t i = 0; i < {}; i++) {{'
.format(num_elems))
subcalls.append('{} v;'.format(f.fieldtype.name))
if f.fieldtype.is_assignable():
subcalls.append('v = fromwire_{}(&cursor, plen);'
.format(f.fieldtype.name, basetype))
subcalls.append('v = fromwire_{}({}cursor, {}plen);'
.format(f.fieldtype.name, basetype, ref, ref))
else:
# We don't handle this yet!
assert(basetype not in varlen_structs)

subcalls.append('fromwire_{}(&cursor, &plen, &v);'
.format(basetype))
subcalls.append('fromwire_{}({}cursor, {}plen, &v);'
.format(basetype, ref, ref))

self.add_truncate_check(subcalls)
self.add_truncate_check(subcalls, truncate_check_ref)

subcalls.append('printwire_{}(tal_fmt(NULL, "%s.{}", fieldname), &v);'
.format(basetype, f.name))
subcalls.append('}')
subcalls.append('printf("]");')

def print_printwire(self, is_header):
def print_printwire(self, is_header, is_tlv=False):
template = printwire_header_templ if is_header else printwire_impl_templ
fields = ['\t{} {};\n'.format(f.fieldtype.name, f.name) for f in self.fields if f.is_len_var]

tlv_args = '' if not is_tlv else ', size_t *plen'
ref = '&' if not is_tlv else ''
truncate_check_ref = '' if not is_tlv else '*'

toplevel_msg_setup = ''
if not is_tlv:
toplevel_msg_setup = printwire_toplevel_tmpl.format(enum=self.enum)

subcalls = CCode()
for f in self.fields:
basetype = f.fieldtype.base()
Expand All @@ -752,50 +762,59 @@ def print_printwire(self, is_header):
subcalls.append('/*{} */'.format(c))

if f.is_len_var:
subcalls.append('{} {} = fromwire_{}(&cursor, &plen);'
.format(f.fieldtype.name, f.name, basetype))
self.add_truncate_check(subcalls)
if f.fieldtype.is_var_int():
subcalls.append('{} {} = fromwire_{}({}cursor, {}plen);'
.format(basetype, f.name, 'var_int', ref, ref))
else:
subcalls.append('{} {} = fromwire_{}({}cursor, {}plen);'
.format(f.fieldtype.name, f.name, basetype, ref, ref))
self.add_truncate_check(subcalls, truncate_check_ref)
continue

subcalls.append('printf("{}=");'.format(f.name))
if f.is_padding():
subcalls.append('printwire_pad(tal_fmt(NULL, "%s.{}", fieldname), &cursor, &plen, {});'
.format(f.name, f.num_elems))
self.add_truncate_check(subcalls)
subcalls.append('printwire_pad(tal_fmt(NULL, "%s.{}", fieldname), {}cursor, {}plen, {});'
.format(f.name, ref, ref, f.num_elems))
self.add_truncate_check(subcalls, truncate_check_ref)
elif f.is_array():
self.print_printwire_array(subcalls, basetype, f, f.num_elems)
self.add_truncate_check(subcalls)
self.print_printwire_array(subcalls, basetype, f, f.num_elems, ref)
self.add_truncate_check(subcalls, truncate_check_ref)
elif f.is_variable_size():
self.print_printwire_array(subcalls, basetype, f, f.lenvar)
self.add_truncate_check(subcalls)
self.print_printwire_array(subcalls, basetype, f, f.lenvar, ref)
self.add_truncate_check(subcalls, truncate_check_ref)
else:
if f.optional:
subcalls.append("if (fromwire_bool(&cursor, &plen)) {")
subcalls.append("if (fromwire_bool({}cursor, {}plen)) {".format(ref, ref))

if f.is_assignable():
subcalls.append('{} {} = fromwire_{}(&cursor, &plen);'
.format(f.fieldtype.name, f.name, basetype))
subcalls.append('{} {} = fromwire_{}({}cursor, {}plen);'
.format(f.fieldtype.name, f.name, basetype, ref, ref))
else:
# Don't handle these yet.
assert(basetype not in varlen_structs)
subcalls.append('{} {};'.
format(f.fieldtype.name, f.name))
subcalls.append('fromwire_{}(&cursor, &plen, &{});'
.format(basetype, f.name))
subcalls.append('fromwire_{}({}cursor, {}plen, &{});'
.format(basetype, ref, ref, f.name))

self.add_truncate_check(subcalls)
self.add_truncate_check(subcalls, truncate_check_ref)
subcalls.append('printwire_{}(tal_fmt(NULL, "%s.{}", fieldname), &{});'
.format(basetype, f.name, f.name))
if f.optional:
subcalls.append("} else {")
self.add_truncate_check(subcalls)
self.add_truncate_check(subcalls, truncate_check_ref)
subcalls.append("}")

len_check = '' if is_tlv else printwire_lencheck
return template.format(
tlv_args=tlv_args,
name=self.name,
fields=''.join(fields),
enum=self.enum,
subcalls=str(subcalls)
toplevel_msg_setup=toplevel_msg_setup,
subcalls=str(subcalls),
lencheck=len_check,
cursor_ptr=('' if not is_tlv else '*'),
is_internal=('' if not is_tlv else 'static ')
)

def print_struct(self):
Expand Down Expand Up @@ -906,6 +925,28 @@ def print_struct(self):
\t\t\tbreak;
"""

print_tlv_template = """static void printwire_{tlv_name}(const char *fieldname, const u8 *cursor)
{{
\tu8 msg_type;
\tu64 msg_size;
\tsize_t plen = tal_count(cursor);
\twhile (cursor) {{
\t\tmsg_type = fromwire_u8(&cursor, &plen);
\t\tmsg_size = fromwire_var_int(&cursor, &plen);
\t\tif (!cursor)
\t\t\tbreak;
\t\tswitch ((enum {tlv_name}_type)msg_type) {{
\t\t\t{printcases}
\t\t\tdefault:
\t\t\t\tprintf("WARNING:No message matching type %d\\n", msg_type);
\t\t}}
\t}}
\tif (plen != 0)
\t\tprintf("EXTRA: %s\\n", tal_hexstr(NULL, cursor, plen));
}}
"""


def build_tlv_fromwires(tlv_fields):
fromwires = []
Expand Down Expand Up @@ -970,6 +1011,35 @@ def find_message(messages, name):
return None


def print_tlv_printwire(tlv_name, messages):
printcases = ''
for m in messages:
printcases += 'case {enum.name}: printf("{enum.name} (size %"PRIu64"):\\n", msg_size); printwire_{name}("{name}", &cursor, &plen); break;'.format(
enum=m.enum, name=m.name, tlv_name=tlv_name)
return print_tlv_template.format(
tlv_name=tlv_name,
printcases=printcases)


def print_tlv_printwires(is_header, tlv_fields):
if is_header:
return [print_master_header_tlv_template]

decls = []
switches = ''
for name, messages in tlv_fields.items():
# Print each of the message parsers
decls += [m.print_printwire(options.header, is_tlv=True) for m in messages]

# Print the TLV body parser
decls.append(print_tlv_printwire(name, messages))

# Print the 'master' print_tlv_messages cases
switches += tlv_switch_template.format(tlv_name=name)
decls.append(print_master_tlv_template.format(tlv_switches=switches))
return decls


def find_message_with_option(messages, optional_messages, name, option):
fullname = name + "_" + option.replace('-', '_')

Expand Down Expand Up @@ -1169,6 +1239,7 @@ def build_tlv_structs(tlv_fields):
print_template = """/* This file was generated by generate-wire.py */
/* Do not modify this file! Modify the _csv file it was generated from. */
#include "{headerfilename}"
#include <inttypes.h>
#include <ccan/mem/mem.h>
#include <ccan/tal/str/str.h>
#include <common/utils.h>
Expand All @@ -1186,6 +1257,24 @@ def build_tlv_structs(tlv_fields):
{func_decls}
"""

print_master_tlv_template = """
void print_tlv_message(const char *tlv_name, const u8 *msg)
{{
\t{tlv_switches}
\tprintf("ERR: Unknown TLV message type: %s\n", tlv_name);
}}
"""

print_master_header_tlv_template = """void print_tlv_message(const char *tlv_name, const u8 *msg);
"""

tlv_switch_template = """
\tif (strcmp(tlv_name, "{tlv_name}") == 0) {{
\t\tprintwire_{tlv_name}("{tlv_name}", msg);
\t\treturn;
\t}}
"""

idem = re.sub(r'[^A-Z]+', '_', options.headerfilename.upper())
if options.printwire:
if options.header:
Expand All @@ -1207,7 +1296,9 @@ def build_tlv_structs(tlv_fields):
printcases = ['case {enum.name}: printf("{enum.name}:\\n"); printwire_{name}("{name}", msg); return;'.format(enum=m.enum, name=m.name) for m in toplevel_messages]

if options.printwire:
decls = [m.print_printwire(options.header) for m in messages + messages_with_option]
decls = [m.print_printwire(options.header) for m in toplevel_messages + messages_with_option]
if len(tlv_fields):
decls += print_tlv_printwires(options.header, tlv_fields)
else:
towire_decls = []
fromwire_decls = []
Expand Down

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