diff options
Diffstat (limited to 'editcap.c')
| -rw-r--r-- | editcap.c | 67 |
1 files changed, 37 insertions, 30 deletions
@@ -734,9 +734,9 @@ usage(gboolean is_error) fprintf(output, " chop at the packet beginning, negative values at the\n"); fprintf(output, " packet end. If an optional offset precedes the length,\n"); fprintf(output, " then the bytes chopped will be offset from that value.\n"); - fprintf(output, " Offsets are expected to be positive values, regardless\n"); - fprintf(output, " of chopping from packet beginning or packet end. You\n"); - fprintf(output, " can use this option more than once.\n"); + fprintf(output, " Positive offsets are from the packet beginning,\n"); + fprintf(output, " negative offsets are from the packet end. You can use\n"); + fprintf(output, " this option more than once.\n"); fprintf(output, " -L adjust the frame length when chopping and/or snapping\n"); fprintf(output, " -t <time adjustment> adjust the timestamp of each packet;\n"); fprintf(output, " <time adjustment> is in relative seconds (e.g. -0.5).\n"); @@ -865,8 +865,8 @@ main(int argc, char *argv[]) guint32 snaplen = 0; /* No limit */ int choplen_begin = 0; /* No chop at beginning */ int choplen_end = 0; /* No chop at end */ - int chopoff_begin = 0; /* Offset when chop from beginning */ - int chopoff_end = 0; /* Offset when chop from end */ + int chopoff_begin_pos = 0, chopoff_begin_neg = 0;/* Offsets for chopping from beginning */ + int chopoff_end_pos = 0, chopoff_end_neg = 0; /* Offset for chopping from end */ gboolean adjlen = FALSE; wtap_dumper *pdh = NULL; unsigned int count = 1; @@ -975,17 +975,10 @@ main(int argc, char *argv[]) choplen = chopoff; chopoff = 0; break; - case 2: /* both an offset and chop length was specified */ - if (chopoff < 0) { - fprintf(stderr, "editcap: \"%s\" isn't a valid chop offset:length\n", - optarg); - exit(1); - } - if (choplen < 0) { - chopoff = -chopoff; - } + case 2: /* both an offset and chop length was specified */ break; + default: fprintf(stderr, "editcap: \"%s\" isn't a valid chop length or offset:length\n", optarg); @@ -993,14 +986,19 @@ main(int argc, char *argv[]) break; } - if (choplen > 0) + if (choplen > 0) { choplen_begin += choplen; - else if (choplen < 0) + if (chopoff > 0) + chopoff_begin_pos += chopoff; + else + chopoff_begin_neg += chopoff; + } else if (choplen < 0) { choplen_end += choplen; - if (chopoff > 0) - chopoff_begin += chopoff; - else if (chopoff < 0) - chopoff_end += chopoff; + if (chopoff > 0) + chopoff_end_pos += chopoff; + else + chopoff_end_neg += chopoff; + } break; } @@ -1333,18 +1331,27 @@ main(int argc, char *argv[]) /* If we're not chopping anything from one side, then the offset for * that side is meaningless. */ if (choplen_begin == 0) - chopoff_begin = 0; + chopoff_begin_pos = chopoff_begin_neg = 0; if (choplen_end == 0) - chopoff_end = 0; + chopoff_end_pos = chopoff_end_neg = 0; + + if (chopoff_begin_neg < 0) { + chopoff_begin_pos += phdr->caplen + chopoff_begin_neg; + chopoff_begin_neg = 0; + } + if (chopoff_end_pos > 0) { + chopoff_end_neg += chopoff_end_pos - phdr->caplen; + chopoff_end_pos = 0; + } /* Make sure we don't chop off more than we have available */ - if (phdr->caplen < (guint32)(chopoff_begin - chopoff_end)) { + if (phdr->caplen < (guint32)(chopoff_begin_pos - chopoff_end_neg)) { choplen_begin = 0; choplen_end = 0; } if ((guint32)(choplen_begin - choplen_end) > - (phdr->caplen - (guint32)(chopoff_begin - chopoff_end))) { - choplen_begin = phdr->caplen - (chopoff_begin - chopoff_end); + (phdr->caplen - (guint32)(chopoff_begin_pos - chopoff_end_neg))) { + choplen_begin = phdr->caplen - (chopoff_begin_pos - chopoff_end_neg); choplen_end = 0; } @@ -1353,8 +1360,8 @@ main(int argc, char *argv[]) if (choplen_begin > 0) { snap_phdr = *phdr; - if (chopoff_begin > 0) { - memmove(&buf[chopoff_begin], &buf[chopoff_begin + choplen_begin], + if (chopoff_begin_pos > 0) { + memmove(&buf[chopoff_begin_pos], &buf[chopoff_begin_pos + choplen_begin], snap_phdr.caplen - choplen_begin); } else { @@ -1377,9 +1384,9 @@ main(int argc, char *argv[]) if (choplen_end < 0) { snap_phdr = *phdr; - if (chopoff_end < 0) { - memmove(&buf[(gint)snap_phdr.caplen + (choplen_end + chopoff_end)], - &buf[(gint)snap_phdr.caplen + chopoff_end], -chopoff_end); + if (chopoff_end_neg < 0) { + memmove(&buf[(gint)snap_phdr.caplen + (choplen_end + chopoff_end_neg)], + &buf[(gint)snap_phdr.caplen + chopoff_end_neg], -chopoff_end_neg); } snap_phdr.caplen += choplen_end; |