Re: [lwip-users] TCIP Support Flow for PPPos
On Mon, Oct 27, 2014 at 10:53:25AM -0700, mjackson wrote: 1. After PPP has completed negotiations (LCP, AUTH and IPCP), which api should I call to connect to a remote server? your application can use the regular lwip mechanisms once the link is up, without special consideration for ppp (eg. udp_sendto); which exactly you need depends on your NO_SYS value, whether you want TCP or UDP etc. 2. After connecting to a remote server, should I used the following api's to send and receive data. - ppp_netif_output_ip4(...) or ppp_write(...) - pppos_input(...) once lcp, auth and ipcp have run, there should be no further need to call ppp specific functions. you do need pppos_input, but you should already have used that to feed incoming bytes to the ppp subsystem during link setup, so just continue to do so. best regards chrysn -- To use raw power is to make yourself infinitely vulnerable to greater powers. -- Bene Gesserit axiom signature.asc Description: Digital signature ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
[lwip-users] hayes commands popping up in ppp stream
hello lwip users, i'd like to keep track of my gsm device's position while a ppp data connection is active. unfortunately, that means that the non-ppp messages (/\r\n+CENG:[0-9,a-f]+\r\n/ in my case) arrive in the same stream as ppp messages. (at least, it appears, they are not fully interleaved). does the lwip ppp stack provide a mechanism to feed back rejected strings somewhere else, or do i need to inspect the ppp stack's internal state from outside, determine whether it is currenlty inside or outside of a frame, and divert \r\n... sequences from it if no frame is currently being received? for reference, i'm working with lwip master branch, and the modem i'm using is a simcom sim900d. apart from the CENG messages, occasional \r\nUNDER-VOLTAGE WARNNING\r\n (sic) messages appear, and those can't be switched off. best regards chrysn -- This may seem a bit weird, but that's okay, because it is weird. -- perldata(1) about perl variables signature.asc Description: Digital signature ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] hayes commands popping up in ppp stream
Hi chrysn, On Fri, Nov 14, 2014 at 10:09:18AM +0100, chrysn wrote: hello lwip users, i'd like to keep track of my gsm device's position while a ppp data connection is active. unfortunately, that means that the non-ppp messages (/\r\n+CENG:[0-9,a-f]+\r\n/ in my case) arrive in the same stream as ppp messages. (at least, it appears, they are not fully interleaved). I feel dazed and confused, is this really a thing which is actually usual in the wild or is it specific to your modem ? AFAIK modems usually use DTR level to switch from data mode to command mode, which is an OOB mechanism so it doesn't need dubious parsing. I know about the pause +++ pause mechanism but it is nowadays rarely used since it is prone to erroneous termination, and +STRING+ is not it. Anyway, maybe you have a way out of that, modems in data mode are in strict binary mode of course so any ASCII parsing of the binary stream should result in a failure... but PPP use HDLC framing and your GSM modem is in charge of creating those HDLC frames as well as sending your ASCII string and I hope they are not overlapping. HDLC frames always start with 0xff 0x03 in case of PPP over serial line, which goes to the following with the added HDLC flags: 0x7e 0xff 0x03 ... 0x7e While your ASCII frame will probably be: 0x7e 0x0d(\r) 0x0a(\n) 0x2b(+) ... 0x7e So you can probably split up those frames without much issue. does the lwip ppp stack provide a mechanism to feed back rejected strings somewhere else, or do i need to inspect the ppp stack's internal state from outside, determine whether it is currenlty inside or outside of a frame, and divert \r\n... sequences from it if no frame is currently being received? Well, this looks like an ugly hack, I am not sure this belong to the lwIP stack, especially if this is specific to one modem. It actually breaks the HDLC framing protocol. HDLC is pretty simple to parse and you don't need to do PPP packet formatting, then you can parse the HDLC stream and split up HDLC valid frames vs ASCII frames in the way your modem specific implementation does and before sending them to lwIP. You don't even need to take care of HDLC byte-escaping because you should not find 0x7e inside a frame, well, 0x7e is also ASCII character ~ and this is at least one reason why it actually breaks the HDLC framing. for reference, i'm working with lwip master branch, and the modem i'm using is a simcom sim900d. apart from the CENG messages, occasional \r\nUNDER-VOLTAGE WARNNING\r\n (sic) messages appear, and those can't be switched off. [libel shield running, empty text here] ;-) Sylvain signature.asc Description: Digital signature ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] Assertion pbuf_free: p-ref 0 failed at line 651 in ../src/lwip/core/pbuf.c
If I was you, I would:
- make sure the port I'm using works, by first running known good examples.
- study those examples to learn how to work with lwip.
- read the wiki, it is great for bed reading.
- trace assertions to my code, execute step by step and see what I'm
doing wrong.
- try to figure it out by myself, but if I can't, I would write a brief
and concise description of what I'm doing, what I can't solve, and what
I don't understand. That description would include a description of the
system in which I'm doing that, stating that I followed the previous
steps and the system works, and what type of lwIP API I'm using.
With the data you provide, I can only direct you to line 651 of pbuf.c
and see why something you are passing to that function is incorrect.
OK, I feel like wasting some time today, here I go:
$ vi src/core/pbuf.c
651
/pbuf_free(struct pbuf *p)/
{
[...]
/* all pbufs in a chain are referenced at least once */
*651--LWIP_ASSERT(pbuf_free: p-ref 0, p-ref 0);*
//* decrease reference count (number of pointers to pbuf) *///
//ref = --(p-ref);/
that means you are trying to free an already freed pbuf.
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Re: [lwip-users] hayes commands popping up in ppp stream
My view: Since PPP expects a serial transparent interface, and you are not providing that, I would write a tap which provides that to PPP and taps all other data out. GSM modem real serial -- my module - PPP virtual serial --- tracking virtual serial Some GSM modems provide a packetization interface to clearly separate muxed channels on the same serial interface. If yours does not, you'll have to work harder. ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] hayes commands popping up in ppp stream
BTW, \r\nUNDER-VOLTAGE WARNING\r\n is a clear indication that your power supply is not well designed and/or your module is not well decoupled. It needs 2A current to transmit for a very short time, you need a 100uF low impedance in parallel with 2uF MLCC close to the module; or better, what the hardware manual recommends. And make sure your power supply can provide that current for that amount of time, which you'll find in the manual. Sorry about that, but I used to work with the tech support for Simcom in Argentina... On 14/11/2014 10:06 a.m., Sergio R. Caprile wrote: My view: Since PPP expects a serial transparent interface, and you are not providing that, I would write a tap which provides that to PPP and taps all other data out. GSM modem real serial -- my module - PPP virtual serial --- tracking virtual serial Some GSM modems provide a packetization interface to clearly separate muxed channels on the same serial interface. If yours does not, you'll have to work harder. -- - Sergio R. Caprile, Human Being, Bs.As., Argentina Electronics Engineer, Musician (guitarist), TaoFx http://www.scaprile.ldir.com.ar/ - ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
[lwip-users] Assertion pbuf_free: p-ref 0 failed at line 651 in ../src/lwip/core/pbuf.c
Hi, I'm trying to send ping and udp packets. But for both packets I'm getting assertion failed like this Assertion pbuf_free: p-ref 0 failed at line 651 in ../src/lwip/core/pbuf.c Can anyone please help me.. Regards, Aaisha Ahmed. ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] Sending to a non-local network without default netif set
In response to the remark: Simon is right: routing doesn't have anything to do with the source address and it shouldn't have to I think Simon is not right (no pun intended). I am not entirely familiar with the ideas behind LwIP. But sourcebased routing is very much in line with rfc1122 (ip for hosts). I quote: Under the Strong ES model, the route computation for an outgoing datagram is the mapping: route(src IP addr, dest IP addr, TOS) - gateway Here the source address is included as a parameter in order to select a gateway that is directly reachable on the corresponding physical interface. Note that this model logically requires that in general there be at least one default gateway, and preferably multiple defaults, for each IP source address. We are facing a similar challenge with our project and we need a similar mechanism. Is the adaptation of the ip_route available somewhere in the community? Regards, Erik van Veelen -- View this message in context: http://lwip.100.n7.nabble.com/Sending-to-a-non-local-network-without-default-netif-set-tp22981p23521.html Sent from the lwip-users mailing list archive at Nabble.com. ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] hayes commands popping up in ppp stream
hello sergio, thank you for your responses. On Fri, Nov 14, 2014 at 10:06:00AM -0300, Sergio R. Caprile wrote: Since PPP expects a serial transparent interface, and you are not providing that, I would write a tap which provides that to PPP and taps all other data out. GSM modem real serial -- my module - PPP virtual serial --- tracking virtual serial Some GSM modems provide a packetization interface to clearly separate muxed channels on the same serial interface. If yours does not, you'll have to work harder. that is what i'm about to implement right now. unless the ascii jabber inbetween contains 0x7e 0xff sequences, that should be doable with reasonable effort. On Fri, Nov 14, 2014 at 10:11:01AM -0300, Sergio R. Caprile wrote: BTW, \r\nUNDER-VOLTAGE WARNING\r\n is a clear indication that your power supply is not well designed and/or your module is not well decoupled. It needs 2A current to transmit for a very short time, you need a 100uF low impedance in parallel with 2uF MLCC close to the module; or better, what the hardware manual recommends. i was afraid so when i first saw them, but i never ran into an UNDER-VOLTAGE POWER DOWN condition so far; thing is, i'm running my entire board off 3.3V, which is the threshold for the warning. the module can do down to 3.2V, and a 2m2 cap in parallel with a 4u7 and 100n make sure it won't even if the usb power supply doesn't handle bursts well. i hope it's sufficient -- or are you confident that this is indication of trouble even when running on 3v3? Sorry about that, but I used to work with the tech support for Simcom in Argentina... honestly, i wasn't aware that such a thing exists; when it comes to support, nothing the simcom website has looks like you'll ever talk to a technician. could you point me to where i can reach their (possibly local, paid if needed) tech support? best regard chrysn -- Most people would leave. Not us. We're Vikings. We have stubbornness issues. -- Hiccup, son of Stoic signature.asc Description: Digital signature ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] hayes commands popping up in ppp stream
Chrysn, yes, Simcom tech department sucks... they've had some internal issues on the move from SIM340 to SIM900. They are chinese and english docs are poor and mostly non-existent. We've had a tech contact long ago but hopefully I haven't contacted them for years. Regarding the hw, you are too close to the limit, I've never run them bellow 3.6V. You need a heck of a stable power supply to drop only 0.1V with a 2A pull. It might work OK in the lab/city (close to the cell) and fail on a moving truck. Should you need anything else, you can pm me so we don't bother lwIP users. ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] Sending to a non-local network without default netif set
HaaCee2 wrote: I am not entirely familiar with the ideas behind LwIP. But sourcebased routing is very much in line with rfc1122 (ip for hosts). I quote: Under the Strong ES model, the route computation for an outgoing datagram is the mapping: route(src IP addr, dest IP addr, TOS) - gateway Here the source address is included as a parameter in order to select a gateway that is directly reachable on the corresponding physical interface. Note that this model logically requires that in general there be at least one default gateway, and preferably multiple defaults, for each IP source address. Well, that excerpt is one of 2 possibilities in the RFC. The other possibility is to do like lwIP does. I admit though that it looks kind of strange sending packets with IP address A to the interface B just because you have a matching destination gateway on that netif... By now, I'm tempted to add source-based routing as an option, although I expect people using lwIP wih more than one interface being only a small percentage... Simon ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] Sending to a non-local network without default netif set
On 14-11-14 20:27, Simon Goldschmidt [via lwIP] wrote: HaaCee2 wrote: I am not entirely familiar with the ideas behind LwIP. But sourcebased routing is very much in line with rfc1122 (ip for hosts). I quote: Under the Strong ES model, the route computation for an outgoing datagram is the mapping: route(src IP addr, dest IP addr, TOS) - gateway Here the source address is included as a parameter in order to select a gateway that is directly reachable on the corresponding physical interface. Note that this model logically requires that in general there be at least one default gateway, and preferably multiple defaults, for each IP source address. Well, that excerpt is one of 2 possibilities in the RFC. The other possibility is to do like lwIP does. I admit though that it looks kind of strange sending packets with IP address A to the interface B just because you have a matching destination gateway on that netif... You are correct that it is only 1 of the 2 possibilities, and as indicated I am not familiar with the design of lwIP. So it's a perfectly valid choice NOT to support sourcebased routing. By now, I'm tempted to add source-based routing as an option, although I expect people using lwIP wih more than one interface being only a small percentage... I beg to differ In my opinion the best approach to deal with vlans is to have multiple interfaces and then I think one is required to do sourcebased routing. Otherwise datagrams destined for a host on one vlan can be visible on another vlan (which is obviously undesirable). Multiple stacks is a possibility here as well, but in embedded designs hardly an option Erik Simon ___ lwip-users mailing list [hidden email] /user/SendEmail.jtp?type=nodenode=23524i=0 https://lists.nongnu.org/mailman/listinfo/lwip-users If you reply to this email, your message will be added to the discussion below: http://lwip.100.n7.nabble.com/Sending-to-a-non-local-network-without-default-netif-set-tp22981p23524.html To unsubscribe from Sending to a non-local network without default netif set, click here http://lwip.100.n7.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_codenode=22981code=ZXZ2ZWVsZW5AYWltdmFsbGV5Lm5sfDIyOTgxfC01NzI0OTAwNzY=. NAML http://lwip.100.n7.nabble.com/template/NamlServlet.jtp?macro=macro_viewerid=instant_html%21nabble%3Aemail.namlbase=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespacebreadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml -- Erik van Veelen AimValley B.V. Utrechtseweg 38, 1213 TV Hilversum, The Netherlands Tel: +31 35 689 1929, Fax: +31 35 689 1901 AimValley certificate http://www.aimvalley.com/aimvalley-ca-certificate-2007.crt -- View this message in context: http://lwip.100.n7.nabble.com/Sending-to-a-non-local-network-without-default-netif-set-tp22981p23525.html Sent from the lwip-users mailing list archive at Nabble.com.___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] Sending to a non-local network without default netif set
HaaCee2 wrote: I beg to differ I've added a task for this to the tracker: https://savannah.nongnu.org/task/index.php?13397 Simon ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] hayes commands popping up in ppp stream
Hi chrysn, On Fri, Nov 14, 2014 at 05:43:47PM +0100, chrysn wrote: i was afraid so when i first saw them, but i never ran into an UNDER-VOLTAGE POWER DOWN condition so far; thing is, i'm running my entire board off 3.3V, which is the threshold for the warning. the module can do down to 3.2V, and a 2m2 cap in parallel with a 4u7 and 100n make sure it won't even if the usb power supply doesn't handle bursts well. i hope it's sufficient -- or are you confident that this is indication of trouble even when running on 3v3? GSM modems connected to anything else than a li-ion battery should really be powered with a 3.8V 2A-peak low ripple power supply with enough decoupling capacitors (300 µF at least if powered through a DC/DC converter) for them to work correctly. Sylvain signature.asc Description: Digital signature ___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
Re: [lwip-users] hayes commands popping up in ppp stream
Hi, The product is fine,I have been using the SIM900D without any problems in many different countries as well. It may run for a days without dropping the connection. Obviously you have a hardware issue as your not supplying enough voltage or power supply voltage drops when the gsm signal is low and requires 2W. Also it maybe a setup problem. Are you setting up the SIM900d as transparent mode? const char *AT_CIPMODE = AT+CIPMODE=1\r; err = sim_send_recv(AT_CIPMODE,13,buf,length,br); Nick From: chrysn Sent: Friday, 14 November 2014 6:39 PM To: lwip-users@nongnu.org hello lwip users, i'd like to keep track of my gsm device's position while a ppp data connection is active. unfortunately, that means that the non-ppp messages (/\r\n+CENG:[0-9,a-f]+\r\n/ in my case) arrive in the same stream as ppp messages. (at least, it appears, they are not fully interleaved). does the lwip ppp stack provide a mechanism to feed back rejected strings somewhere else, or do i need to inspect the ppp stack's internal state from outside, determine whether it is currenlty inside or outside of a frame, and divert \r\n... sequences from it if no frame is currently being received? for reference, i'm working with lwip master branch, and the modem i'm using is a simcom sim900d. apart from the CENG messages, occasional \r\nUNDER-VOLTAGE WARNNING\r\n (sic) messages appear, and those can't be switched off. best regards chrysn -- This may seem a bit weird, but that's okay, because it is weird. -- perldata(1) about perl variables___ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
