Specifically, is this range legal?
Content-Range: 0-1/12818084
The bytes-unit is missing. Here are the production rules for Content-Range:
Content-Range = "Content-Range" ":" content-range-spec
content-range-spec = byte-content-range-spec
byte-content-range-spec = bytes-unit SP
byte-range-resp-spec "/"
( instance-length | "*" )
byte-range-resp-spec = (first-byte-pos "-" last-byte-pos)
| "*"
instance-length = 1*DIGIT
But with bytes as byte-unit it would be valid:
bytes 0-1/12818084
0 is first-byte-pos
1 is last-byte-pos
12818084 is instance-length
It should be:
Content-Range: bytes 0-1/12818084
According to the RFC, this is legal. There is no minimum limit as long as in Content-Range: bytes a-b/c, a <= b, and c > b.
Practical example: I was able to obtain a 2 byte partial response from mirrors.kernel.org (I checked that I could also get a 1 byte response):
Related
hi I has date format and I want converted to correct GMT date :
<YYMMDDhhmmssNNN><C|D|G|H>
Sample value on that date:
210204215026000C
I get this explanation for part NNN :
NNN If flag is C or D then NNN is the number of hours relativeto GMT,
if flag is G or H, NNN is the number of quarter hours relative to GMT
C|D|G|H C and G = Ahead of GMT, D and H = Behind GMT
but I did not get how number of hours relative to GMT can present on 3 digits ? it should be in 2 digit as i knew the offset for hours related to GMT is from 0 to 23 , and also what quarter hours relative to GMT mean ?
I want to use Scala or Java.
I don’t know why they set 3 digits aside for the offset. I agree with you that 2 digits suffice for all cases. Maybe they just wanted to be very sure they would never run of out space, and maybe they even overdid this a bit. 3 digits is not a problem as long as the actual values are within the range that java.time.ZoneOffset can handle, +/-18 hours. In your example NNN is 000, so 0 hours from GMT, which certainly is OK and trivial to handle.
A quarter hour is a quarter of an hour. As Salman A mentioned in a comment, 22 quarter hours ahead of Greenwich means an offset of +05:30, currently used in Sri Lanka and India. If the producer of the string wants to use this option, they can give numbers up to 72 (still comfortably within 2 digits). 18 * 4 = 72, so 18 hours equals 72 quarter hours. To imagine a situation where 2 digits would be too little, think an offset of 25 hours. I wouldn’t think it realistic, on the other hand no one can guarantee that it will never happen.
Java solution: how to parse and convert to GMT time
I am using these constants:
private static final Pattern DATE_PATTERN
= Pattern.compile("(\\d{12})(\\d{3})(\\w)");
private static final DateTimeFormatter FORMATTER
= DateTimeFormatter.ofPattern("uuMMddHHmmss");
private static final int SECONDS_IN_A_QUARTER_HOUR
= Math.toIntExact(Duration.ofHours(1).dividedBy(4).getSeconds());
Parse and convert like this:
String sampleValue = "210204215026000C";
Matcher matcher = DATE_PATTERN.matcher(sampleValue);
if (matcher.matches()) {
LocalDateTime ldt = LocalDateTime.parse(matcher.group(1), FORMATTER);
int offsetAmount = Integer.parseInt(matcher.group(2));
char flag = matcher.group(3).charAt(0);
// offset amount denotes either hours or quarter hours
boolean quarterHours = flag == 'G' || flag == 'H';
boolean negative = flag == 'D' || flag == 'H';
if (negative) {
offsetAmount = -offsetAmount;
}
ZoneOffset offset = quarterHours
? ZoneOffset.ofTotalSeconds(offsetAmount * SECONDS_IN_A_QUARTER_HOUR)
: ZoneOffset.ofHours(offsetAmount);
OffsetDateTime dateTime = ldt.atOffset(offset);
OffsetDateTime gmtDateTime = dateTime.withOffsetSameInstant(ZoneOffset.UTC);
System.out.println("GMT time: " + gmtDateTime);
}
else {
System.out.println("Invalid value: " + sampleValue);
}
Output is:
GMT time: 2021-02-04T21:50:26Z
I think my code covers all valid cases. You will probably want to validate that the flag is indeed C, D, G or H, and also handle the potential DateTimeException and NumberFormatException from the parsing and creating the ZoneOffset (NumberFormatException should not happen).
I am trying to send an HTTP GET request to google.com, but the answer I get is an ACK and not the HTML file. Here is the code:
def Make_Get():
synR = IP(dst = 'www.google.com', ttl = 64)/TCP(dport = 80,sport = randint(1024,65535), flags = 'S')
synAckAN = sr1(synR)
req = (IP(dst='www.google.com') / TCP(dport=80, sport=synAckAN[TCP].dport, seq=synAckAN[TCP].ack, ack=synAckAN[TCP].seq + 1, flags='A')/"GET / HTTP/1.0 \n\n")
ans, a = sr(req)
return ans
and this are the two packets I got in return of this function:
###[ IP ]###
version = 4
ihl = None
tos = 0x0
len = None
id = 1
flags =
frag = 0
ttl = 64
proto = tcp
chksum = None
src = 192.168.233.128
dst = 216.58.214.100
\options \
###[ TCP ]###
sport = 35534
dport = http
seq = 1
ack = 1964930533
dataofs = None
reserved = 0
flags = A
window = 8192
chksum = None
urgptr = 0
options = {}
###[ Raw ]###
load = 'GET / HTTP/1.0 \n\n'
None
###[ IP ]###
version = 4L
ihl = 5L
tos = 0x0
len = 40
id = 32226
flags =
frag = 0L
ttl = 128
proto = tcp
chksum = 0x6425
src = 216.58.214.100
dst = 192.168.233.128
\options \
###[ TCP ]###
sport = http
dport = 35534
seq = 1964930533
ack = 18
dataofs = 5L
reserved = 0L
flags = A
window = 64240
chksum = 0xe5e6
urgptr = 0
options = {}
###[ Padding ]###
load = '\x00\x00\x00\x00\x00\x00'
None
When I sniffed the traffic while I sent this packet, I got this:
###[ Ethernet ]###
dst= 00:0c:29:bb:8e:79
src= 00:50:56:e9:b8:b1
type= 0x800
###[ IP ]###
version= 4L
ihl= 5L
tos= 0x0
len= 517
id= 32136
flags=
frag= 0L
ttl= 128
proto= tcp
chksum= 0x5004
src= 172.217.20.100
dst= 192.168.233.128
\options\
###[ TCP ]###
sport= http
dport= 1928
seq= 1828330545
ack= 18
dataofs= 5L
reserved= 0L
flags= FPA
window= 64240
chksum= 0x8b5f
urgptr= 0
options= []
###[ HTTP ]###
###[ HTTP Response ]###
Status-Line= u'HTTP/1.0 302 Found'
Accept-Ranges= None
Age= None
E-Tag= None
Location= u'http://www.google.co.il/?gfe_rd=cr&ei=9fiTV6P6FuWg8weei7rQDA'
Proxy-Authenticate= None
Retry-After= None
Server= None
Vary= None
WWW-Authenticate= None
Cache-Control= u'private'
Connection= None
Date= u'Sat, 23 Jul 2016 23:08:37 GMT'
Pragma= None
Trailer= None
Transfer-Encoding= None
Upgrade= None
Via= None
Warning= None
Keep-Alive= None
Allow= None
Content-Encoding= None
Content-Language= None
Content-Length= u'261'
Content-Location= None
Content-MD5= None
Content-Range= None
Content-Type= u'text/html; charset=UTF-8'
Expires= None
Last-Modified= None
Headers= u'Date: Sat, 23 Jul 2016 23:08:37 GMT\r\nContent-Length: 261\r\nContent-Type: text/html; charset=UTF-8\r\nLocation: http://www.google.co.il/?gfe_rd=cr&ei=9fiTV6P6FuWg8weei7rQDA\r\nCache-Control: private'
Additional-Headers= None
###[ Raw ]###
load= '<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">\n<TITLE>302 Moved</TITLE></HEAD><BODY>\n<H1>302 Moved</H1>\nThe document has moved\nhere.\r\n</BODY></HTML>\r\n'
As you can see, the last layer in this one, contain the code I need.
my question is:
Why don't I get the packet with sr() and how can I obtain it to collect the HTML code?
EDIT:
The call to the function:
print Make_Get('www.google.com')[0][Raw]
The function:
def Make_Get(ipp):
ip = DNS_Req(ipp)
synR = IP(dst = ip)/TCP(dport = 80,sport = randint(1024,65535), flags = 'S')
syn_ack = sr1(synR)
getStr = "GET / HTTP/1.1\r\nHost: {}\r\n\r\n".format(ip)
request = (IP(dst= ip) / TCP(dport=80, sport=syn_ack[TCP].dport, seq=syn_ack[TCP].ack, ack=syn_ack[TCP].seq + 1, flags='A')/getStr)
an = sr(request)
return an
The resuls:
Begin emission:
.Finished to send 1 packets.
*
Received 2 packets, got 1 answers, remaining 0 packets
Begin emission:
*Finished to send 1 packets.
Received 1 packets, got 1 answers, remaining 0 packets
[]
First, in HTTP, a correct newline is "\r\n", not "\n".
Second, is there any reason why you use HTTP/1.0 and not HTTP/1.1? If not, you should change your request to:
GET / HTTP/1.1\r\n
Host: www.google.com\r\n
\r\n
Third, the ACK you are getting is usually sent by the server before sending the actual HTTP response to acknowledge your request faster. A second segment is then sent with the HTTP response. You are missing this one in your first show() example.
Have a look here.
To catch this segment, you can use sr() function with its parameter timeout and multi:
ans, unans = sr(request, timeout=2, multi=True)
for c, s in ans:
if s.haslayer(Raw):
print b[Raw]
print("-----------") # just a delimiter
timeout is used to ensure that sr() will stop (value 2 is arbitrary).
multi mean "accept multiple answers for the same stimulus" unless it is there, sr() will stop sniffing after one answer to the request sent.
I have no idea what im doing I need to decode mmZ\dxZmx]Zpgy, I have an example but not sure what to do please help!
If (EncryptedChar - Key < 32) then
DecryptedChar = ((EncryptedChar - Key) + 127) - 32
Else
DecryptedChar = (EncryptedChar - Key)
the key us unknown 1-100
Use ord and chr to convert between the ordinals (ord) of the ASCII value and the and the characters (chr) they represent.
Then you can loop through your string and apply the your algorithm to each.
For example:
import sys
SecretMessage = "mmZ\dxZmx]Zpgy"
Key = 88
for Letter in SecretMessage:
EncryptedChar = ord(Letter)
if (EncryptedChar - Key) < 32:
DecryptedChar = ((EncryptedChar - Key) + 127) - 32
else:
DecryptedChar = (EncryptedChar - Key)
sys.stdout.write(chr(DecryptedChar))
Run this to see the output. I'll leave the exercise of finding the key value 88 up to you (hint: it involves iterations). You also appear to be missing the first letter from SecretMessage (probably a :).
I've been using httr to export data from REDCap databases into R for a few months now. We recently upgraded our R Studio Server to the most recent version (v0.98.1049) and upgraded to R 3.1.1 at the same time. After that upgrade, my httr::POST calls stopped working, sometimes. The error I keep getting is
Error in function (type, msg, asError = TRUE) :
GnuTLS recv error (-9): A TLS packet with unexpected length was received.
At first I thought it might be an SSL issue, but the error only occurs in certain databases, and in those databases, I can still download the data using RCurl. That is, this code will work
RCurl::postForm(uri=[URL],
.params=list(token=[TOKEN],
content='record',
format='csv'))
But this code will not
httr::POST(url=[URL],
body=list(token=[TOKEN],
content='record',
format='csv'))
Adding further to my confusion, even though I can't export data in projects where this error occurs, I can import data.
I'm out of ideas on where to start. I'd much appreciate any ideas on what might be going wrong here.
(I'd like to provide a reproducible example, but I'm afraid I'm working with healthcare data. sorry)
As requested, here's the verbose() output. It's a slightly different call, but produces the same error. (I used a call that wouldn't risk exposing confidential information)
> httr::POST(url=whi$url,
+ body=list(token=whi$token,
+ content='metadata',
+ format='csv'),
+ httr::verbose(data_in=TRUE, info=TRUE))
* Hostname was found in DNS cache
* Hostname in DNS cache was stale, zapped
* Trying 172.26.30.4...
* Connected to [URL] (172.26.30.4) port 443 (#7)
* found 153 certificates in /home/nutterb/R/x86_64-unknown-linux-gnu-library/3.1/httr/cacert.pem
* SSL re-using session ID
* server certificate verification OK
* common name: [URL] (matched)
* server certificate expiration date OK
* server certificate activation date OK
* certificate public key: RSA
* certificate version: #3
* subject: OU=Domain Control Validated,CN=[URL]
* start date: Thu, 10 Apr 2014 17:06:17 GMT
*
* expire date: Sat, 21 Mar 2015 16:35:07 GMT
*
* issuer: C=US,ST=Arizona,L=Scottsdale,O=Starfield Technologies\, Inc.,OU=http://certs.starfieldtech.com/repository/,CN=Starfield Secure Certificate Authority - G2
* compression: NULL
* cipher: AES-128-CBC
* MAC: SHA1
-> POST /redcap/api/ HTTP/1.1
-> User-Agent: curl/7.35.0 Rcurl/1.95.4.1 httr/0.5.0.9000
-> Host: [URL]
-> Accept-Encoding: gzip
-> accept: application/json, text/xml, */*
-> Content-Length: 374
-> Expect: 100-continue
-> Content-Type: multipart/form-data; boundary=------------------------05c968969cc362a9
->
<- HTTP/1.1 100 Continue
>> --------------------------05c968969cc362a9
>> Content-Disposition: form-data; name="token"
>>
>> [TOKEN]
>> --------------------------05c968969cc362a9
>> Content-Disposition: form-data; name="content"
>>
>> metadata
>> --------------------------05c968969cc362a9
>> Content-Disposition: form-data; name="format"
>>
>> csv
>> --------------------------05c968969cc362a9--
<- HTTP/1.1 200 OK
<- Date: Sat, 06 Sep 2014 09:55:43 GMT
<- Expires: 0
<- cache-control: no-store, no-cache, must-revalidate
<- Pragma: no-cache
<- Access-Control-Allow-Origin: *
<- Vary: Accept-Encoding
<- Content-Type: text/html; charset=utf-8
<- Connection: close
<- Content-Encoding: gzip
<-
<< NA
<< NA
<< NA
<< NA
<< NA
<< NA
<< NA
<< NA
<< NA
<< NA
<< NA
* GnuTLS recv error (-9): A TLS packet with unexpected length was received.
* Closing connection 7
Error in function (type, msg, asError = TRUE) :
GnuTLS recv error (-9): A TLS packet with unexpected length was received.
In addition: There were 11 warnings (use warnings() to see them)
> warnings()
Warning messages:
1: In strsplit(x, "\n", fixed = TRUE) : input string 1 is invalid in this locale
2: In strsplit(x, "\n", fixed = TRUE) : input string 1 is invalid in this locale
3: In strsplit(x, "\n", fixed = TRUE) : input string 1 is invalid in this locale
4: In strsplit(x, "\n", fixed = TRUE) : input string 1 is invalid in this locale
5: In strsplit(x, "\n", fixed = TRUE) : input string 1 is invalid in this locale
6: In strsplit(x, "\n", fixed = TRUE) : input string 1 is invalid in this locale
7: In strsplit(x, "\n", fixed = TRUE) : input string 1 is invalid in this locale
8: In strsplit(x, "\n", fixed = TRUE) : input string 1 is invalid in this locale
9: In strsplit(x, "\n", fixed = TRUE) : input string 1 is invalid in this locale
10: In strsplit(x, "\n", fixed = TRUE) : input string 1 is invalid in this locale
11: In strsplit(x, "\n", fixed = TRUE) : input string 1 is invalid in this locale
>
I am running the AT command AT+KCELL to get cell information and it returns, amongst other things, a PLMN (Public Land and Mobile Network) - the description of this from the documentation is:
PLMN identifiers (3 bytes), made of MCC (Mobile Country Code), and MNC
(Mobile Network Code).
OK, that matches what Wikipedia says - in there is the MCC and MNC. Now what I don't understand is how do I extract the aforementioned MCC and MNC values?
Here is an example. I get back:
32f210
and I am told (though I am sceptical) that that should result in:
MNC: 1
MCC: 232
but I can't for the life of me work out how to get that result from the PLMN so how do I parse this?
Well, I have found this out and figured I would add an answer here in case there is some other unlucky soul who has to do this - the PDF called GSM Technical Specification (section 10.2.4) contains the answer, the relevant bit is:
PLMN Contents: Mobile Country Code (MCC) followed by the Mobile Network Code (MNC). Coding: according to TS GSM 04.08 [14].
If storage
for fewer than the maximum possible number n is required, the excess
bytes shall be set to 'FF'. For instance, using 246 for the MCC and 81
for the MNC and if this is the first and only PLMN, the contents reads
as follows: Bytes 1-3: '42' 'F6' '18' Bytes 4-6: 'FF' 'FF' 'FF' etc.
So I was wrong to be sceptical!
I need to read from the left swapping the digits around so the first two bytes would be the MCC so that would be 232f and the MNC would be 01 then I just discard the f and I have 232 and 1! Glad that one is sorted.
For example, in c# you can do it like this:
string plmn = "whatever the plmn is";
string mcc = new string(plmn.Substring(0, 2).Reverse().ToArray())
+ new string(plmn.Substring(2, 2).Reverse().ToArray())
.Replace('f', ' ')
.Trim();
string mnc = new string(plmn.Substring(4, 2).Reverse().ToArray())
.Replace('f', ' ')
.Trim();
Here is a java answer with bitwise operations:
public static String mcc(byte[] plmnId) {
if (plmnId == null || plmnId.length != 3)
throw new IllegalArgumentException(String.format("Wrong plmnid %s", Arrays.toString(plmnId)));
int a1 = plmnId[0] & 0x0F;
int a2 = (plmnId[0] & 0xF0) >> 4;
int a3 = plmnId[1] & 0x0F;
return "" + a1 + a2 + a3;
}
public static String mnc(byte[] plmnId) {
if (plmnId == null || plmnId.length != 3)
throw new IllegalArgumentException(String.format("Wrong plmnid %s", Arrays.toString(plmnId)));
int a1 = plmnId[2] & 0x0F;
int a2 = (plmnId[2] & 0xF0) >> 4;
int a3 = (plmnId[1] & 0xF0) >> 4;
if (a3 == 15)
return "" + a1 + a2;
else
return "" + a1 + a2 + a3;
}