OpenWrt – Blame information for rev 3
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Rev | Author | Line No. | Line |
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1 | office | 1 | pppd: Watch out for time warps |
2 | |||
3 | On many embedded systems there is no battery backed RTC and a proper system |
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4 | time only becomes available through NTP after establishing a connection. |
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5 | |||
6 | When the clock suddenly jumps forward, the internal accounting (connect time) |
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7 | is confused resulting in unreliable data. |
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8 | |||
9 | This patch implements periodic clock checking to look for time warps, if one |
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10 | is detected, the internal counters are adjusted accordingly. |
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11 | |||
12 | Signed-off-by: Jo-Philipp Wich <jo@mein.io> |
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13 | |||
14 | --- a/pppd/main.c |
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15 | +++ b/pppd/main.c |
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16 | @@ -90,6 +90,7 @@ |
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17 | #include <sys/socket.h> |
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18 | #include <netinet/in.h> |
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19 | #include <arpa/inet.h> |
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20 | +#include <sys/sysinfo.h> |
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21 | |||
22 | #include "pppd.h" |
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23 | #include "magic.h" |
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24 | @@ -228,6 +229,7 @@ static struct subprocess *children; |
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25 | |||
26 | /* Prototypes for procedures local to this file. */ |
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27 | |||
28 | +static void check_time(void); |
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29 | static void setup_signals __P((void)); |
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30 | static void create_pidfile __P((int pid)); |
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31 | static void create_linkpidfile __P((int pid)); |
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3 | office | 32 | @@ -535,6 +537,7 @@ main(argc, argv) |
1 | office | 33 | info("Starting link"); |
34 | } |
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35 | |||
36 | + check_time(); |
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37 | gettimeofday(&start_time, NULL); |
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38 | script_unsetenv("CONNECT_TIME"); |
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39 | script_unsetenv("BYTES_SENT"); |
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3 | office | 40 | @@ -1267,6 +1270,36 @@ struct callout { |
1 | office | 41 | |
42 | static struct callout *callout = NULL; /* Callout list */ |
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43 | static struct timeval timenow; /* Current time */ |
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44 | +static long uptime_diff = 0; |
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45 | +static int uptime_diff_set = 0; |
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46 | + |
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47 | +static void check_time(void) |
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48 | +{ |
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49 | + long new_diff; |
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50 | + struct timeval t; |
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51 | + struct sysinfo i; |
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52 | + struct callout *p; |
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53 | + |
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54 | + gettimeofday(&t, NULL); |
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55 | + sysinfo(&i); |
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56 | + new_diff = t.tv_sec - i.uptime; |
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57 | + |
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58 | + if (!uptime_diff_set) { |
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59 | + uptime_diff = new_diff; |
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60 | + uptime_diff_set = 1; |
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61 | + return; |
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62 | + } |
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63 | + |
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64 | + if ((new_diff - 5 > uptime_diff) || (new_diff + 5 < uptime_diff)) { |
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65 | + /* system time has changed, update counters and timeouts */ |
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66 | + info("System time change detected."); |
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67 | + start_time.tv_sec += new_diff - uptime_diff; |
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68 | + |
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69 | + for (p = callout; p != NULL; p = p->c_next) |
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70 | + p->c_time.tv_sec += new_diff - uptime_diff; |
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71 | + } |
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72 | + uptime_diff = new_diff; |
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73 | +} |
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74 | |||
75 | /* |
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76 | * timeout - Schedule a timeout. |
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3 | office | 77 | @@ -1337,6 +1370,8 @@ calltimeout() |
1 | office | 78 | { |
79 | struct callout *p; |
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80 | |||
81 | + check_time(); |
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82 | + |
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83 | while (callout != NULL) { |
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84 | p = callout; |
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85 | |||
3 | office | 86 | @@ -1364,6 +1399,8 @@ timeleft(tvp) |
1 | office | 87 | { |
88 | if (callout == NULL) |
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89 | return NULL; |
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90 | + |
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91 | + check_time(); |
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92 | |||
93 | gettimeofday(&timenow, NULL); |
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94 | tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec; |