commit c67909d977b2129155c526b9a91514ed56e1f7aa
parent 49a5ee9ac8780be916b54087c79ab3a882760147
Author: Jordan Ritter <jpr5@darkridge.com>
Date: Wed, 6 Sep 2017 17:27:41 -0700
Fallback fix for VLAN & related problems
Building off of the disable-VLAN-auto-inclusion fix, if we encounter a
problem with the PCAP filter, now we just disable VLAN from being
included in the filter and blindly try a second time.
This patch organizes the big initialization pieces into separate
routines to make the retry easier.
Diffstat:
| M | ngrep.c | | | 290 | +++++++++++++++++++++++++++++++++++++++++++------------------------------------ |
| M | ngrep.h | | | 4 | ++++ |
2 files changed, 161 insertions(+), 133 deletions(-)
diff --git a/ngrep.c b/ngrep.c
@@ -367,11 +367,74 @@ int main(int argc, char **argv) {
/* Setup PCAP input */
+ if (setup_pcap_source())
+ clean_exit(2);
+
+ /* Setup BPF filter */
+
+ if (setup_bpf_filter(argv)) {
+ include_vlan = 0;
+ if (filter) { free(filter); filter = NULL; }
+
+ if (setup_bpf_filter(argv)) {
+ pcap_perror(pd, "pcap");
+ clean_exit(2);
+ }
+ }
+
+ if (filter) {
+ if (quiet < 2)
+ printf("filter: %s\n", filter);
+ free(filter);
+ }
+
+ /* Setup matcher */
+
+ if (match_data) {
+ if (setup_matcher())
+ clean_exit(2);
+
+ if (quiet < 2 && strlen(match_data))
+ printf("%smatch: %s%s\n", invert_match?"don't ":"",
+ (bin_data && !strchr(match_data, 'x'))?"0x":"", match_data);
+
+ if (re_match_word) free(match_data);
+ }
+
+ /* Misc */
+
+ if (dump_file) {
+ pd_dump = pcap_dump_open(pd, dump_file);
+ if (!pd_dump) {
+ fprintf(stderr, "fatal: %s\n", pcap_geterr(pd));
+ clean_exit(2);
+ } else printf("output: %s\n", dump_file);
+ }
+
+ update_windowsize(0);
+
+#if defined(_WIN32)
+ win32_initwinsock();
+#endif
+
+#if !defined(_WIN32) && USE_DROPPRIVS
+ drop_privs();
+#endif
+
+ while (pcap_loop(pd, -1, (pcap_handler)process, 0));
+
+ clean_exit(0);
+
+ /* NOT REACHED */
+ return 0;
+}
+
+int setup_pcap_source(void) {
if (read_file) {
if (!(pd = pcap_open_offline(read_file, pc_err))) {
perror(pc_err);
- clean_exit(2);
+ return 1;
}
live_read = 0;
@@ -388,12 +451,12 @@ int main(int argc, char **argv) {
if (!dev) {
perror(pc_err);
- clean_exit(2);
+ return 1;
}
if ((pd = pcap_open_live(dev, snaplen, promisc, to, pc_err)) == NULL) {
perror(pc_err);
- clean_exit(2);
+ return 1;
}
if (pcap_lookupnet(dev, &net.s_addr, &mask.s_addr, pc_err) == -1) {
@@ -412,8 +475,6 @@ int main(int argc, char **argv) {
}
}
- /* Setup link header offset */
-
switch(pcap_datalink(pd)) {
case DLT_EN10MB:
link_offset = ETHHDR_SIZE;
@@ -481,11 +542,13 @@ int main(int argc, char **argv) {
default:
fprintf(stderr, "fatal: unsupported interface type %u\n", pcap_datalink(pd));
- clean_exit(2);
+ return 1;
}
- /* Setup BPF filter */
+ return 0;
+}
+int setup_bpf_filter(char **argv) {
if (filter_file) {
char buf[1024] = {0};
FILE *f = fopen(filter_file, "r");
@@ -499,10 +562,8 @@ int main(int argc, char **argv) {
filter = get_filter_from_string(buf);
- if (pcap_compile(pd, &pcapfilter, filter, 0, mask.s_addr)) {
- pcap_perror(pd, "pcap compile");
- clean_exit(2);
- }
+ if (pcap_compile(pd, &pcapfilter, filter, 0, mask.s_addr))
+ return 1;
} else if (argv[optind]) {
filter = get_filter_from_argv(&argv[optind]);
@@ -514,167 +575,130 @@ int main(int argc, char **argv) {
#if USE_PCAP_RESTART
PCAP_RESTART_FUNC();
#endif
- if (pcap_compile(pd, &pcapfilter, filter, 0, mask.s_addr)) {
- pcap_perror(pd, "pcap compile");
- clean_exit(2);
- } else match_data = NULL;
+
+ if (pcap_compile(pd, &pcapfilter, filter, 0, mask.s_addr))
+ return 1;
+
+ match_data = NULL;
}
} else {
filter = include_vlan ? strdup(BPF_TEMPLATE_IP_VLAN) : strdup(BPF_TEMPLATE_IP);
- if (pcap_compile(pd, &pcapfilter, filter, 0, mask.s_addr)) {
- pcap_perror(pd, "pcap compile");
- clean_exit(2);
- }
+ if (pcap_compile(pd, &pcapfilter, filter, 0, mask.s_addr))
+ return 1;
}
- if (filter && quiet < 2)
- printf("filter: %s\n", filter);
+ if (pcap_setfilter(pd, &pcapfilter))
+ return 1;
- if (pcap_setfilter(pd, &pcapfilter)) {
- pcap_perror(pd, "pcap set");
- clean_exit(2);
- }
-
- /* Setup matcher */
+ return 0;
+}
- if (match_data) {
- if (bin_match) {
- uint32_t i = 0, n;
- uint32_t len;
- char *s, *d;
+int setup_matcher(void) {
+ if (bin_match) {
+ uint32_t i = 0, n;
+ uint32_t len;
+ char *s, *d;
- if (re_match_word || re_ignore_case) {
- fprintf(stderr, "fatal: regex switches are incompatible with binary matching\n");
- clean_exit(2);
- }
+ if (re_match_word || re_ignore_case) {
+ fprintf(stderr, "fatal: regex switches are incompatible with binary matching\n");
+ return 1;
+ }
- len = (uint32_t)strlen(match_data);
- if (len % 2 != 0 || !strishex(match_data)) {
- fprintf(stderr, "fatal: invalid hex string specified\n");
- clean_exit(2);
- }
+ len = (uint32_t)strlen(match_data);
+ if (len % 2 != 0 || !strishex(match_data)) {
+ fprintf(stderr, "fatal: invalid hex string specified\n");
+ return 1;
+ }
- bin_data = (char*)malloc(len / 2);
- memset(bin_data, 0, len / 2);
- d = bin_data;
+ bin_data = (char*)malloc(len / 2);
+ memset(bin_data, 0, len / 2);
+ d = bin_data;
- if ((s = strchr(match_data, 'x')))
- len -= (uint32_t)(++s - match_data - 1);
- else s = match_data;
+ if ((s = strchr(match_data, 'x')))
+ len -= (uint32_t)(++s - match_data - 1);
+ else s = match_data;
- while (i <= len) {
- sscanf(s+i, "%2x", &n);
- *d++ = n;
- i += 2;
- }
+ while (i <= len) {
+ sscanf(s+i, "%2x", &n);
+ *d++ = n;
+ i += 2;
+ }
- match_len = len / 2;
- match_func = &bin_match_func;
+ match_len = len / 2;
+ match_func = &bin_match_func;
- } else {
+ } else {
#if USE_PCRE
- uint32_t pcre_options = PCRE_UNGREEDY;
+ uint32_t pcre_options = PCRE_UNGREEDY;
- if (re_ignore_case)
- pcre_options |= PCRE_CASELESS;
+ if (re_ignore_case)
+ pcre_options |= PCRE_CASELESS;
- if (re_multiline_match)
- pcre_options |= PCRE_DOTALL;
+ if (re_multiline_match)
+ pcre_options |= PCRE_DOTALL;
#else
- re_syntax_options = RE_CHAR_CLASSES | RE_NO_BK_PARENS | RE_NO_BK_VBAR |
- RE_CONTEXT_INDEP_ANCHORS | RE_CONTEXT_INDEP_OPS;
+ re_syntax_options = RE_CHAR_CLASSES | RE_NO_BK_PARENS | RE_NO_BK_VBAR |
+ RE_CONTEXT_INDEP_ANCHORS | RE_CONTEXT_INDEP_OPS;
- if (re_multiline_match)
- re_syntax_options |= RE_DOT_NEWLINE;
+ if (re_multiline_match)
+ re_syntax_options |= RE_DOT_NEWLINE;
- if (re_ignore_case) {
- uint32_t i;
- char *s;
+ if (re_ignore_case) {
+ uint32_t i;
+ char *s;
- pattern.translate = (char*)malloc(256);
- s = pattern.translate;
+ pattern.translate = (char*)malloc(256);
+ s = pattern.translate;
- for (i = 0; i < 256; i++)
- s[i] = i;
- for (i = 'A'; i <= 'Z'; i++)
- s[i] = i + 32;
+ for (i = 0; i < 256; i++)
+ s[i] = i;
+ for (i = 'A'; i <= 'Z'; i++)
+ s[i] = i + 32;
- s = match_data;
- while (*s) {
- *s = tolower(*s);
- s++;
- }
+ s = match_data;
+ while (*s) {
+ *s = tolower(*s);
+ s++;
+ }
- } else pattern.translate = NULL;
+ } else pattern.translate = NULL;
#endif
- if (re_match_word) {
- char *word_regex = (char*)malloc(strlen(match_data) * 3 + strlen(WORD_REGEX));
- sprintf(word_regex, WORD_REGEX, match_data, match_data, match_data);
- match_data = word_regex;
- }
+ if (re_match_word) {
+ char *word_regex = (char*)malloc(strlen(match_data) * 3 + strlen(WORD_REGEX));
+ sprintf(word_regex, WORD_REGEX, match_data, match_data, match_data);
+ match_data = word_regex;
+ }
#if USE_PCRE
- pattern = pcre_compile(match_data, pcre_options, (const char **)&re_err, &err_offset, 0);
+ pattern = pcre_compile(match_data, pcre_options, (const char **)&re_err, &err_offset, 0);
- if (!pattern) {
- fprintf(stderr, "compile failed: %s\n", re_err);
- clean_exit(2);
- }
+ if (!pattern) {
+ fprintf(stderr, "compile failed: %s\n", re_err);
+ return 1;
+ }
- pattern_extra = pcre_study(pattern, 0, (const char **)&re_err);
+ pattern_extra = pcre_study(pattern, 0, (const char **)&re_err);
#else
- re_err = re_compile_pattern(match_data, strlen(match_data), &pattern);
- if (re_err) {
- fprintf(stderr, "regex compile: %s\n", re_err);
- clean_exit(2);
- }
-
- pattern.fastmap = (char*)malloc(256);
- if (re_compile_fastmap(&pattern)) {
- perror("fastmap compile failed");
- clean_exit(2);
- }
-#endif
-
- match_func = &re_match_func;
+ re_err = re_compile_pattern(match_data, strlen(match_data), &pattern);
+ if (re_err) {
+ fprintf(stderr, "regex compile: %s\n", re_err);
+ return 1;
}
- if (quiet < 2 && match_data && strlen(match_data))
- printf("%smatch: %s%s\n", invert_match?"don't ":"",
- (bin_data && !strchr(match_data, 'x'))?"0x":"", match_data);
- }
-
- if (filter) free(filter);
- if (re_match_word) free(match_data);
-
-
- if (dump_file) {
- pd_dump = pcap_dump_open(pd, dump_file);
- if (!pd_dump) {
- fprintf(stderr, "fatal: %s\n", pcap_geterr(pd));
- clean_exit(2);
- } else printf("output: %s\n", dump_file);
- }
-
- update_windowsize(0);
-
-#if defined(_WIN32)
- win32_initwinsock();
-#endif
-
-#if !defined(_WIN32) && USE_DROPPRIVS
- drop_privs();
+ pattern.fastmap = (char*)malloc(256);
+ if (re_compile_fastmap(&pattern)) {
+ perror("fastmap compile failed");
+ return 1;
+ }
#endif
- while (pcap_loop(pd, -1, (pcap_handler)process, 0));
-
- clean_exit(0);
+ match_func = &re_match_func;
+ }
- /* NOT REACHED */
return 0;
}
diff --git a/ngrep.h b/ngrep.h
@@ -108,6 +108,10 @@ typedef enum {
* Prototypes function signatures.
*/
+int setup_pcap_source(void);
+int setup_bpf_filter(char **);
+int setup_matcher(void);
+
void process(u_char *, struct pcap_pkthdr *, u_char *);
void version(void);